{"id":2583,"date":"2021-10-14T16:25:56","date_gmt":"2021-10-14T23:25:56","guid":{"rendered":"https:\/\/www.xh86.me\/?p=2583"},"modified":"2021-10-14T16:25:56","modified_gmt":"2021-10-14T23:25:56","slug":"mysql-%e4%b9%8b%e5%9f%ba%e7%a1%80%e5%91%bd%e4%bb%a4%e7%b2%be%e7%ae%80%e7%ac%94%e8%ae%b0","status":"publish","type":"post","link":"https:\/\/www.xh86.me\/?p=2583","title":{"rendered":"MySQL \u4e4b\u57fa\u7840\u547d\u4ee4(\u7cbe\u7b80\u7b14\u8bb0)"},"content":{"rendered":"

\u25c6\u6570\u636e\u5e93\u76f8\u5173\u547d\u4ee4\u25c6<\/h3>\n

\u521b\u5efa\u6570\u636e\u5e93\uff1a<\/strong>\u00a0\u521b\u5efa\u6570\u636e\u5e93\u53ef\u4ee5\u4f7f\u7528Create database\u547d\u4ee4\uff0c\u521b\u5efa\u4e00\u4e2alyshark\u6570\u636e\u5e93\uff0c\u5e76\u67e5\u770b\u3002<\/p>\n

MariaDB [(none)]> create database lyshark charset utf8;<\/p>\n

Query OK, 1 row affected (0.00 sec)<\/p>\n

MariaDB [(none)]> show create database lyshark\\G<\/p>\n

+———-+——————————————————————+<\/p>\n

| Database | Create Database |<\/p>\n

+———-+——————————————————————+<\/p>\n

| lyshark | CREATE DATABASE `lyshark` \/*!40100 DEFAULT CHARACTER SET utf8 *\/ |<\/p>\n

+———-+——————————————————————+<\/p>\n

\u67e5\u8be2\u6570\u636e\u5e93\uff1a<\/strong>\u00a0\u67e5\u8be2\u6570\u636e\u5e93\u53ef\u4ee5\u4f7f\u7528Show databases\u547d\u4ee4\uff0c\u4e5f\u53ef\u4ee5\u901a\u8fc7like\u9650\u5b9a\u67e5\u8be2\u7ed3\u679c\u3002<\/p>\n

MariaDB [(none)]> show databases;<\/p>\n

+——————–+<\/p>\n

| Database |<\/p>\n

+——————–+<\/p>\n

| information_schema |<\/p>\n

| lyshark |<\/p>\n

| mysql |<\/p>\n

| performance_schema |<\/p>\n

+——————–+<\/p>\n

4 rows in set (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [(none)]> show databases like ‘lys%’;<\/p>\n

+—————–+<\/p>\n

| Database (lys%) |<\/p>\n

+—————–+<\/p>\n

| lyshark |<\/p>\n

+—————–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u66f4\u65b0\u6570\u636e\u5e93\uff1a<\/strong>\u00a0\u5c06\u6570\u636e\u5e93\u7684\u5b57\u7b26\u96c6\u4ece utf8 \u4fee\u6539\u4e3agbk\u683c\u5f0f\u3002<\/p>\n

MariaDB [(none)]> alter database lyshark charset gbk;<\/p>\n

Query OK, 1 row affected (0.00 sec)<\/p>\n

MariaDB [(none)]> show create database lyshark;<\/p>\n

+———-+—————————————————————–+<\/p>\n

| Database | Create Database |<\/p>\n

+———-+—————————————————————–+<\/p>\n

| lyshark | CREATE DATABASE `lyshark` \/*!40100 DEFAULT CHARACTER SET gbk *\/ |<\/p>\n

+———-+—————————————————————–+<\/p>\n

\u5220\u9664\u6570\u636e\u5e93\uff1a<\/strong>\u00a0\u624b\u52a8\u5220\u9664\u6570\u636e\u5e93\u00a0lyshark\u5e76\u67e5\u8be2\u3002<\/p>\n

MariaDB [(none)]> drop database lyshark;<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [(none)]> show databases;<\/p>\n

+——————–+<\/p>\n

| Database |<\/p>\n

+——————–+<\/p>\n

| information_schema |<\/p>\n

| mysql |<\/p>\n

| performance_schema |<\/p>\n

+——————–+<\/p>\n

3 rows in set (0.00 sec)<\/p>\n

 <\/p>\n

\u25c6\u6570\u636e\u8868\u76f8\u5173\u547d\u4ee4\u25c6<\/h3>\n

\u521b\u5efa\u6570\u636e\u8868\uff1a<\/strong>\u00a0\u521b\u5efalyshark\u5e93,\u7528\u6765\u5b58\u50a8\u8868\u7ed3\u6784,\u5e76\u6307\u5b9a\u91c7\u7528utf8\u7f16\u7801,\u5728\u8be5\u6570\u636e\u5e93\u4e2d\u521b\u5efatb_user\u8868.<\/p>\n

MariaDB [(none)]> create database lyshark charset utf8;<\/p>\n

Query OK, 1 row affected (0.00 sec)<\/p>\n

MariaDB [(none)]> use lyshark<\/p>\n

Database changed<\/p>\n

MariaDB [lyshark]> create table tb_user<\/p>\n

-> (<\/p>\n

-> id int(11),<\/p>\n

-> name varchar(25),<\/p>\n

-> deptId int(11),<\/p>\n

-> salary float<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.01 sec)<\/p>\n

\u67e5\u8be2\u8868\u7ed3\u6784\uff1a<\/strong>\u00a0\u5728MySQL\u4e2d,\u67e5\u770b\u8868\u7ed3\u6784\u53ef\u4ee5\u4f7f\u7528describe\u548cshow create table\u8bed\u53e5.<\/p>\n

MariaDB [lyshark]> describe lyshark;<\/p>\n

+——–+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——–+————-+——+—–+———+—————-+<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(20) | NO | | NULL | |<\/p>\n

| salary | float | YES | | NULL | |<\/p>\n

+——–+————-+——+—–+———+—————-+<\/p>\n

3 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> show create table lyshark \\G<\/p>\n

*************************** 1. row ***************************<\/p>\n

Table: lyshark<\/p>\n

Create Table: CREATE TABLE `lyshark` (<\/p>\n

`id` int(10) NOT NULL AUTO_INCREMENT,<\/p>\n

`name` varchar(20) NOT NULL,<\/p>\n

`salary` float DEFAULT NULL,<\/p>\n

PRIMARY KEY (`id`)<\/p>\n

) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u5b9a\u4e49\u5355\u5b57\u6bb5\u4e3b\u952e\uff1a<\/strong>\u00a0\u521b\u5efa\u8868tab_1\u5c06id\u5b57\u6bb5\u5b9a\u4e49\u4e3aprimary key\u4e3b\u952e,\u5176SQL\u8bed\u53e5\u7684\u5199\u6cd5\u5982\u4e0b.<\/p>\n

MariaDB [lyshark]> create table tab_1<\/p>\n

-> (<\/p>\n

-> id int(10),<\/p>\n

-> name varchar(20),<\/p>\n

-> deptid int(10),<\/p>\n

-> salary float,<\/p>\n

-> primary key(id)<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.01 sec)<\/p>\n

\u5b9a\u4e49\u591a\u5b57\u6bb5\u4e3b\u952e\uff1a<\/strong>\u00a0\u521b\u5efa\u8868tab_2,\u5c06name\u5b57\u6bb5\u4e0edeptid\u5b57\u6bb5\u7ec4\u5408\u5728\u4e00\u8d77,\u6210\u4e3atab_2\u7684\u591a\u5b57\u6bb5\u8054\u5408\u4e3b\u952e.<\/p>\n

MariaDB [lyshark]> create table tab_2<\/p>\n

-> (<\/p>\n

-> name varchar(20),<\/p>\n

-> deptid int(10),<\/p>\n

-> salary float,<\/p>\n

-> primary key(name,deptid)<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

\u4f7f\u7528\u975e\u7a7a\u7ea6\u675f\uff1a<\/strong>\u00a0\u521b\u5efa\u8868tab_3,\u6307\u5b9aname\u5b57\u6bb5\u4e0d\u80fd\u4e3a\u7a7a,\u4e3a\u7a7a\u5219\u62a5\u9519\u8bef.<\/p>\n

MariaDB [lyshark]> create table tab_4<\/p>\n

-> (<\/p>\n

-> id int(10) primary key,<\/p>\n

-> name varchar(20) not null,<\/p>\n

-> salary float<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

\u4f7f\u7528\u9ed8\u8ba4\u7ea6\u675f\uff1a<\/strong>\u00a0\u521b\u5efa\u8868tab_4,\u6307\u5b9asalary\u5b57\u6bb5\u81ea\u52a8\u9ed8\u8ba4\u5de5\u8d44\u4e3a500,\u5982\u4e0d\u586b\u5199\u6b64\u9879\u9ed8\u8ba4\u662f500.<\/p>\n

MariaDB [lyshark]> create table tab_4<\/p>\n

-> (<\/p>\n

-> id int(10) primary key,<\/p>\n

-> name varchar(20) not null,<\/p>\n

-> salary float default 500<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

\u4f7f\u7528\u552f\u4e00\u7ea6\u675f\uff1a<\/strong>\u00a0\u521b\u5efa\u8868tab_5,\u5e76\u6307\u5b9a\u5b57\u6bb5name\u5217\u552f\u4e00,\u5141\u8bb8\u4e3a\u7a7a,\u4f46\u53ea\u80fd\u51fa\u73b0\u4e00\u4e2a\u7a7a\u503c,\u552f\u4e00\u7ea6\u675f\u53ef\u4ee5\u786e\u4fdd\u6570\u636e\u4e0d\u91cd\u590d.<\/p>\n

MariaDB [lyshark]> create table tab_5<\/p>\n

-> (<\/p>\n

-> id int(10) primary key,<\/p>\n

-> name varchar(20),<\/p>\n

-> location varchar(50),<\/p>\n

-> constraint sth unique(name)<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

\u6ce8\u610f\uff1aunique\u548cprimary key\u7684\u533a\u522b\uff0c\u4e00\u4e2a\u8868\u53ef\u4ee5\u6709\u591a\u4e2a\u5b57\u6bb5\u58f0\u660e\u6210unique,\u4f46\u53ea\u80fd\u6709\u4e00\u4e2aprimary key\u58f0\u660e.<\/p>\n

\u8bbe\u7f6e\u8868\u81ea\u589e\u957f\uff1a<\/strong>\u00a0\u521b\u5efa\u8868tab_6\u6307\u5b9aid\u5458\u5de5\u7f16\u53f7\u4e3a\u81ea\u52a8\u589e\u957f\u6a21\u5f0f,\u5e76\u63d2\u5165\u6570\u636e,\u7701\u7565ID\u7f16\u53f7\u8fd9\u4e00\u680f\u5373\u53ef.<\/p>\n

MariaDB [lyshark]> create table tab_6<\/p>\n

-> (<\/p>\n

-> id int(10) primary key auto_increment,<\/p>\n

-> name varchar(20) not null,<\/p>\n

-> salary float<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> insert into tab_8(name,salary) values(‘lyshark’,1000),(‘admin’,200);<\/p>\n

MariaDB [lyshark]> select * from tab_8;<\/p>\n

+—-+———+——–+<\/p>\n

| id | name | salary |<\/p>\n

+—-+———+——–+<\/p>\n

| 1 | lyshark | 1000 |<\/p>\n

| 2 | admin | 200 |<\/p>\n

+—-+———+——–+<\/p>\n

2 rows in set (0.00 sec)<\/p>\n

\u4f7f\u7528\u5916\u952e\u7ea6\u675f\uff1a<\/strong>\u00a0\u5916\u952e\u7528\u6765\u5728\u4e24\u4e2a\u8868\u7684\u6570\u636e\u4e4b\u95f4\u5efa\u7acb\u8fde\u63a5,\u6bcf\u4e2a\u5916\u952e\u503c\u5fc5\u987b\u7b49\u4e8e\u53e6\u4e00\u4e2a\u8868\u4e2d\u4e3b\u952e\u7684\u67d0\u4e2a\u503c.<\/p>\n

1.\u521b\u5efa\u4e00\u4e2atb_dept\u5e76\u6307\u5b9a\u4e3a\u4e3b\u8868,\u628atb_emp\u6307\u5b9a\u4e3a\u4ece\u8868,\u5c06\u4e24\u8868\u6307\u5b9a\u5b57\u6bb5\u76f8\u5173\u8054.<\/p>\n

MariaDB [lyshark]> create table tb_dept<\/p>\n

-> (<\/p>\n

-> id int(11) primary key,<\/p>\n

-> name varchar(22) NOT NULL,<\/p>\n

-> location varchar(50)<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.01 sec)<\/p>\n

2.\u63a5\u7740\u521b\u5efa\u6570\u636e\u8868tb_emp,\u8ba9\u5b83\u7684deptid\u5b57\u6bb5,\u4f5c\u4e3a\u5916\u952e\u5173\u8054\u5230tb_dept\u7684\u4e3b\u952eid\u5b57\u6bb5\u4e0a.<\/p>\n

MariaDB [lyshark]> create table tb_emp<\/p>\n

-> (<\/p>\n

-> id int(10) primary key,<\/p>\n

-> name varchar(25),<\/p>\n

-> deptid int(10),<\/p>\n

-> salary float,<\/p>\n

-> constraint fk_empdept foreign key(deptid) references tb_dept(id)<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

3.\u4ee5\u4e0a\u8bed\u53e5\u6267\u884c,\u5728\u8868tb_emp\u4e0a\u6dfb\u52a0\u4e86\u540d\u79f0\u4e3afk_empdept\u7684\u5916\u952e\u7ea6\u675f,\u5916\u952e\u5b57\u6bb5\u4e3adeptid,\u5176\u4f9d\u8d56\u4e8etb_dept\u8868\u4e2d\u7684,\u4e3b\u952eid.<\/p>\n

MariaDB [lyshark]> desc tb_dept;<\/p>\n

+———-+————-+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———-+————-+——+—–+———+——-+<\/p>\n

| id | int(11) | NO | PRI | NULL | |<\/p>\n

| name | varchar(22) | NO | | NULL | |<\/p>\n

| location | varchar(50) | YES | | NULL | |<\/p>\n

+———-+————-+——+—–+———+——-+<\/p>\n

3 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> desc tb_emp;<\/p>\n

+——–+————-+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——–+————-+——+—–+———+——-+<\/p>\n

| id | int(10) | NO | PRI | NULL | |<\/p>\n

| name | varchar(25) | YES | | NULL | |<\/p>\n

| deptid | int(10) | YES | MUL | NULL | |<\/p>\n

| salary | float | YES | | NULL | |<\/p>\n

+——–+————-+——+—–+———+——-+<\/p>\n

4 rows in set (0.00 sec)<\/p>\n

 <\/p>\n

\u4fee\u6539\u5b57\u6bb5\u4e0e\u6570\u636e<\/h2>\n

 <\/p>\n

\u25c6\u64cd\u4f5c\u8868\u4e2d\u5b57\u6bb5\u25c6<\/h3>\n

\u4fee\u6539\u8868\u540d\u79f0\uff1a<\/strong>\u00a0\u901a\u8fc7alter table\u8bed\u53e5,\u5c06\u6570\u636e\u8868tab_1,\u6539\u540d\u6210lyshark.<\/p>\n

MariaDB [lyshark]> show tables;<\/p>\n

+——————-+<\/p>\n

| Tables_in_lyshark |<\/p>\n

+——————-+<\/p>\n

| tab_1 |<\/p>\n

+——————-+<\/p>\n

1 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> alter table tab rename to lyshark;<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> show tables;<\/p>\n

+——————-+<\/p>\n

| Tables_in_lyshark |<\/p>\n

+——————-+<\/p>\n

| lyshark |<\/p>\n

+——————-+<\/p>\n

1 rows in set (0.00 sec)<\/p>\n

\u4fee\u6539\u5b57\u6bb5\u540d\uff1a<\/strong>\u00a0\u5c06\u8868\u4e2dtab_test\u7684salary\u5b57\u6bb5\u540d\u6539\u4e3alyshark\u5e76\u4fee\u6539\u6570\u636e\u7c7b\u578b\u4e3avarchar(30).<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+——–+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——–+————-+——+—–+———+—————-+<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| salary | float | YES | | NULL | |<\/p>\n

+——–+————-+——+—–+———+—————-+<\/p>\n

3 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> alter table tab_test change salary lyshark varchar(30);<\/p>\n

Query OK, 4 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

3 rows in set (0.00 sec)<\/p>\n

\u53ea\u4fee\u6539\u5b57\u6bb5\u7c7b\u578b\uff1a<\/strong>\u00a0\u5c06\u8868tab_test\u7684name\u5b57\u6bb5\u6570\u636e\u7c7b\u578b\u7531varchar(20)\u4fee\u6539\u4e3avarchar(40).<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+——–+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——–+————-+——+—–+———+—————-+<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(20) | NO | | NULL | |<\/p>\n

| salary | float | YES | | NULL | |<\/p>\n

+——–+————-+——+—–+———+—————-+<\/p>\n

3 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> alter table tab_test modify name varchar(40);<\/p>\n

Query OK, 4 rows affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+——–+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——–+————-+——+—–+———+—————-+<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| salary | float | YES | | NULL | |<\/p>\n

+——–+————-+——+—–+———+—————-+<\/p>\n

3 rows in set (0.00 sec)<\/p>\n

\u5728\u672b\u5c3e\u6dfb\u52a0\u5b57\u6bb5\uff1a<\/strong>\u00a0\u5728tab_test\u8868,\u7ed3\u5c3e\u6dfb\u52a0clound\u5b57\u6bb5,\u7c7b\u578b\u4e3avarchar(20),\u5e76\u5177\u6709not null\u5c5e\u6027.<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

| manager | int(10) | YES | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

4 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> alter table tab_test add clound varchar(20) not null;<\/p>\n

Query OK, 4 rows affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

| manager | int(10) | YES | | NULL | |<\/p>\n

| clound | varchar(20) | NO | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

5 rows in set (0.00 sec)<\/p>\n

\u5728\u5f00\u5934\u6dfb\u52a0\u5b57\u6bb5\uff1a<\/strong>\u00a0\u5728tab_test\u8868\u7684\u7b2c\u4e00\u5217\u6dfb\u52a0\u4e00\u4e2a\u65b0\u5b57\u6bb5,\u5b57\u6bb5\u540dwang\u7c7b\u578bint(4).<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

| manager | int(10) | YES | | NULL | |<\/p>\n

| clound | varchar(20) | NO | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

5 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> alter table tab_test add wang int(4) first;<\/p>\n

Query OK, 4 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| wang | int(4) | YES | | NULL | |<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

| manager | int(10) | YES | | NULL | |<\/p>\n

| clound | varchar(20) | NO | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

6 rows in set (0.00 sec)<\/p>\n

\u5728\u6307\u5b9a\u4f4d\u7f6e\u6dfb\u52a0\u5b57\u6bb5\uff1a<\/strong>\u00a0\u5728tab_test\u8868\u7684\u6307\u5b9a\u4f4d\u7f6e\u6dfb\u52a0\u4e00\u4e2a\u5b57\u6bb5,\u5728name\u5217\u7684\u540e\u9762\u63d2\u5165\u4e00\u4e2axxxx\u5b57\u6bb5\u7c7b\u578b\u4e3aint.<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| wang | int(4) | YES | | NULL | |<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

| manager | int(10) | YES | | NULL | |<\/p>\n

| clound | varchar(20) | NO | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

6 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> alter table tab_test add xxxx int(4) after name;<\/p>\n

Query OK, 4 rows affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| wang | int(4) | YES | | NULL | |<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| xxxx | int(4) | YES | | NULL | |<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

| manager | int(10) | YES | | NULL | |<\/p>\n

| clound | varchar(20) | NO | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

7 rows in set (0.00 sec)<\/p>\n

\u5220\u9664\u8868\u4e2d\u6307\u5b9a\u5b57\u6bb5\uff1a<\/strong>\u00a0\u4f7f\u7528alert table drop\u547d\u4ee4,\u5220\u9664tab_test\u8868\u4e2d\u7684clound\u5b57\u6bb5.<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| wang | int(4) | YES | | NULL | |<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| xxxx | int(4) | YES | | NULL | |<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

| manager | int(10) | YES | | NULL | |<\/p>\n

| clound | varchar(20) | NO | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

7 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> alter table tab_test drop clound;<\/p>\n

Query OK, 4 rows affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| wang | int(4) | YES | | NULL | |<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| xxxx | int(4) | YES | | NULL | |<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

| manager | int(10) | YES | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

6 rows in set (0.00 sec)<\/p>\n

\u4fee\u6539\u5b57\u6bb5\u6392\u5217\u5230\u7b2c\u4e00\u5217\uff1a<\/strong>\u00a0\u5c06tab_test\u8868\u4e2d\u7684lyshark\u5b57\u6bb5\u79fb\u52a8\u5230\u7b2c1\u5217.<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| wang | int(4) | YES | | NULL | |<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| xxxx | int(4) | YES | | NULL | |<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

| manager | int(10) | YES | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

6 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> alter table tab_test modify lyshark varchar(30) first;<\/p>\n

Query OK, 4 rows affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

| wang | int(4) | YES | | NULL | |<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| xxxx | int(4) | YES | | NULL | |<\/p>\n

| manager | int(10) | YES | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

6 rows in set (0.01 sec)<\/p>\n

\u4fee\u6539\u6307\u5b9a\u5b57\u6bb5\u5230\u4efb\u610f\u4f4d\u7f6e:<\/strong>\u00a0\u628atab_test\u8868\u4e2d\u7684manager\u5b57\u6bb5\u653e\u5230lyshark\u5b57\u6bb5\u7684\u540e\u9762.<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

| wang | int(4) | YES | | NULL | |<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| xxxx | int(4) | YES | | NULL | |<\/p>\n

| manager | int(10) | YES | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

6 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> alter table tab_test modify manager int(10) after lyshark;<\/p>\n

Query OK, 4 rows affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> desc tab_test;<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

| lyshark | varchar(30) | YES | | NULL | |<\/p>\n

| manager | int(10) | YES | | NULL | |<\/p>\n

| wang | int(4) | YES | | NULL | |<\/p>\n

| id | int(10) | NO | PRI | NULL | auto_increment |<\/p>\n

| name | varchar(40) | YES | | NULL | |<\/p>\n

| xxxx | int(4) | YES | | NULL | |<\/p>\n

+———+————-+——+—–+———+—————-+<\/p>\n

6 rows in set (0.00 sec)<\/p>\n

\u4fee\u6539\u8868\u7684\u5b58\u50a8\u5f15\u64ce\uff1a<\/strong>\u00a0\u4f7f\u7528show create table\u67e5\u770b\u5f15\u64ce,\u5e76\u4fee\u6539tab_test\u8868\u7684\u9ed8\u8ba4\u5b58\u50a8\u5f15\u64ce\u4e3aMyISAM.<\/p>\n

MariaDB [lyshark]> show create table tab_test \\G<\/p>\n

MariaDB [lyshark]> alter table tab_test engine=MyISAM;<\/p>\n

MariaDB [lyshark]> show create table tab_test \\G<\/p>\n

*************************** 1. row ***************************<\/p>\n

Table: tab_test<\/p>\n

Create Table: CREATE TABLE `tab_test` (<\/p>\n

`lyshark` varchar(30) DEFAULT NULL,<\/p>\n

`manager` int(10) DEFAULT NULL,<\/p>\n

`wang` int(4) DEFAULT NULL,<\/p>\n

`id` int(10) NOT NULL AUTO_INCREMENT,<\/p>\n

`name` varchar(40) DEFAULT NULL,<\/p>\n

`xxxx` int(4) DEFAULT NULL,<\/p>\n

PRIMARY KEY (`id`)<\/p>\n

) ENGINE=MyISAM AUTO_INCREMENT=5 DEFAULT CHARSET=latin1 #\u53ef\u4ee5\u770b\u5230\u5df2\u7ecf\u6539\u53d8\u4e86<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MySQL\u4e2d\u4e3b\u8981\u5b58\u50a8\u5f15\u64ce\u6709:MyISAM\u3001InnoDB\u3001MEMORY\u3001BDB\u3001FEDERATED\u7b49.<\/p>\n

\u5220\u9664\u8868\u7684\u5916\u952e\u7ea6\u675f\uff1a<\/strong>\u00a0\u4f7f\u7528drop foreign key\u547d\u4ee4\u5220\u9664\u5916\u952e\uff0c\u5220\u9664tb_emp\u7684\u5916\u952e\u7ea6\u675f<\/p>\n

MariaDB [lyshark]> desc tb_emp;<\/p>\n

+——–+————-+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——–+————-+——+—–+———+——-+<\/p>\n

| id | int(10) | NO | PRI | NULL | |<\/p>\n

| name | varchar(25) | YES | | NULL | |<\/p>\n

| deptid | int(10) | YES | MUL | NULL | | #\u5916\u952e\u6807\u8bc6MUL<\/p>\n

| salary | float | YES | | NULL | |<\/p>\n

+——–+————-+——+—–+———+——-+<\/p>\n

4 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> show create table tb_emp \\G<\/p>\n

*************************** 1. row ***************************<\/p>\n

Table: tb_emp<\/p>\n

CONSTRAINT `fk_empdept` FOREIGN KEY (`deptid`) REFERENCES `tb_dept` (`id`) #foreign key\u6307\u5b9a\u4e86\u5916\u952e<\/p>\n

) ENGINE=InnoDB DEFAULT CHARSET=latin1<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> alter table tb_emp drop foreign key fk_empdept; #\u5220\u9664tb_emp\u8868\u4e2d\u7684\u5916\u952efk_empdept<\/p>\n

MariaDB [lyshark]> show create table tb_emp \\G<\/p>\n

*************************** 1. row ***************************<\/p>\n

Table: tb_emp<\/p>\n

KEY `fk_empdept` (`deptid`)<\/p>\n

) ENGINE=InnoDB DEFAULT CHARSET=latin1 #\u6b64\u65f6\u5df2\u7ecf\u6ca1\u6709foreign key \u8fd9\u4e00\u9879\u4e86\uff0c\u8bf4\u660e\u5220\u9664\u6210\u529f<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u5220\u9664\u6307\u5b9a\u8868\uff1a<\/strong>\u00a0\u5220\u9664lyshark\u6570\u636e\u5e93\u4e2d\u7684tab_test\u8868\u7ed3\u6784.<\/p>\n

MariaDB [lyshark]> drop table if exists tab_test;<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> show tables;<\/p>\n

+——————-+<\/p>\n

| Tables_in_lyshark |<\/p>\n

+——————-+<\/p>\n

+——————-+<\/p>\n

10 rows in set (0.01 sec)<\/p>\n

 <\/p>\n

\u25c6\u64cd\u4f5c\u8868\u4e2d\u6570\u636e\u25c6<\/h3>\n

\u521b\u5efa\u4e00\u4e2a\u6570\u636e\u8868\uff1a<\/strong>\u00a0\u4e3a\u4e86\u65b9\u4fbf\u540e\u7eed\u7684\u7ec3\u4e60,\u6211\u4eec\u5148\u6765\u521b\u5efa\u4e00\u4e2a\u8868\u7ed3\u6784,SQL\u8bed\u53e5\u5982\u4e0b:<\/p>\n

MariaDB [lyshark]> create table person<\/p>\n

-> (<\/p>\n

-> id int unsigned not null auto_increment,<\/p>\n

-> name char(50) not null default ”,<\/p>\n

-> age int not null default 0,<\/p>\n

-> info char(50) null,<\/p>\n

-> primary key(id)<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

\u5728\u6240\u6709\u5b57\u6bb5\u63d2\u5165\u6570\u636e\uff1a<\/strong>\u00a0\u5728person\u8868\u4e2d,\u63d2\u5165\u4e00\u6761\u65b0\u8bb0\u5f55id=1,name=LyShark,age=22,info=Lawyer,SQL\u8bed\u53e5\u5982\u4e0b:<\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

Empty set (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> insert into person(id,name,age,info) values(1,’LyShark’,22,’Lawyer’);<\/p>\n

Query OK, 1 row affected (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+——–+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+——–+<\/p>\n

| 1 | LyShark | 22 | Lawyer |<\/p>\n

+—-+———+—–+——–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u5728\u6307\u5b9a\u5b57\u6bb5\u63d2\u5165\u6570\u636e\uff1a<\/strong>\u00a0\u5728person\u8868\u4e2d,\u63d2\u5165\u4e00\u6761\u65b0\u8bb0\u5f55,name=Willam,age=18,info=sports,\u6211\u4eec\u4e0d\u7ed9\u5176\u6307\u5b9aID,SQL\u8bed\u53e5\u5982\u4e0b:<\/p>\n

MariaDB [lyshark]> desc person;<\/p>\n

+——-+——————+——+—–+———+—————-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+——————+——+—–+———+—————-+<\/p>\n

| id | int(10) unsigned | NO | PRI | NULL | auto_increment |<\/p>\n

| name | char(50) | NO | | | |<\/p>\n

| age | int(11) | NO | | 0 | |<\/p>\n

| info | char(50) | YES | | NULL | |<\/p>\n

+——-+——————+——+—–+———+—————-+<\/p>\n

4 rows in set (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> insert into person(name,age,info) values(‘Willam’,18,’sports man’);<\/p>\n

Query OK, 1 row affected (0.04 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+————+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+————+<\/p>\n

| 1 | LyShark | 22 | Lawyer |<\/p>\n

| 2 | Willam | 18 | sports man |<\/p>\n

+—-+———+—–+————+<\/p>\n

2 rows in set (0.00 sec)<\/p>\n

\u540c\u65f6\u4e3a\u8868\u63d2\u5165\u591a\u6761\u8bb0\u5f55\uff1a<\/strong>\u00a0\u5728person\u8868\u4e2d,\u540c\u65f6\u63d2\u51653\u6761\u65b0\u8bb0\u5f55,\u6709\u591a\u6761\u53ea\u9700\u8981\u5728\u6bcf\u4e00\u6761\u7684\u540e\u9762\u52a0,\u5373\u53ef,SQL\u8bed\u53e5\u5982\u4e0b:<\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+————+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+————+<\/p>\n

| 1 | LyShark | 22 | Lawyer |<\/p>\n

| 2 | Willam | 18 | sports man |<\/p>\n

+—-+———+—–+————+<\/p>\n

2 rows in set (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> insert into person(name,age,info) values(‘Evans’,27,’secretary’),<\/p>\n

-> (‘Dale’,22,’cook’),<\/p>\n

-> (‘Edison’,28,’singer’);<\/p>\n

Query OK, 3 rows affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+————+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+————+<\/p>\n

| 1 | LyShark | 22 | Lawyer |<\/p>\n

| 2 | Willam | 18 | sports man |<\/p>\n

| 3 | Evans | 27 | secretary |<\/p>\n

| 4 | Dale | 22 | cook |<\/p>\n

| 5 | Edison | 28 | singer |<\/p>\n

+—-+———+—–+————+<\/p>\n

5 rows in set (0.00 sec)<\/p>\n

\u5c06\u67e5\u8be2\u7ed3\u679c\u63d2\u5165\u5230\u8868\u4e2d\uff1a<\/strong>\u00a0\u65b0\u5efa\u4e00\u4e2aperson_old\u8868,\u5176\u8868\u7ed3\u6784\u548cperson\u76f8\u540c,\u6211\u4eec\u5c06person_old\u8868\u4e2d\u7684\u5185\u5bb9\u5168\u90e8\u8fc1\u79fb\u5230person\u4e2d\u53bb,SQL\u8bed\u53e5\u5982\u4e0b:<\/p>\n

1.\u521b\u5efa\u4e00\u4e2aperson_old\u8868,\u5e76\u63d2\u5165\u6d4b\u8bd5\u5b57\u6bb5:<\/p>\n

MariaDB [lyshark]> create table person_old<\/p>\n

-> (<\/p>\n

-> id int unsigned not null auto_increment,<\/p>\n

-> name char(50) not null default ”,<\/p>\n

-> age int not null default 0,<\/p>\n

-> info char(50) null,<\/p>\n

-> primary key(id)<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.01 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> insert into person_old<\/p>\n

-> values(11,’harry’,20,’student’),(12,’Beckham’,33,’police’);<\/p>\n

Query OK, 2 rows affected (0.00 sec)<\/p>\n

Records: 2 Duplicates: 0 Warnings: 0<\/p>\n

2.\u63a5\u4e0b\u6765\u6211\u4eec\u5c06person_old\u8868\u4e2d\u7684\u5185\u5bb9\u8fc1\u79fb\u5230person\u4e2d\u53bb<\/p>\n

MariaDB [lyshark]> select * from person_old;<\/p>\n

+—-+———+—–+———+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+———+<\/p>\n

| 11 | harry | 20 | student |<\/p>\n

| 12 | Beckham | 33 | police |<\/p>\n

+—-+———+—–+———+<\/p>\n

2 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+————+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+————+<\/p>\n

| 1 | LyShark | 22 | Lawyer |<\/p>\n

| 2 | Willam | 18 | sports man |<\/p>\n

| 3 | Evans | 27 | secretary |<\/p>\n

| 4 | Dale | 22 | cook |<\/p>\n

| 5 | Edison | 28 | singer |<\/p>\n

+—-+———+—–+————+<\/p>\n

5 rows in set (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> insert into person(id,name,age,info)<\/p>\n

-> select id,name,age,info from person_old;<\/p>\n

Query OK, 2 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+————+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+————+<\/p>\n

| 1 | LyShark | 22 | Lawyer |<\/p>\n

| 2 | Willam | 18 | sports man |<\/p>\n

| 3 | Evans | 27 | secretary |<\/p>\n

| 4 | Dale | 22 | cook |<\/p>\n

| 5 | Edison | 28 | singer |<\/p>\n

| 11 | harry | 20 | student |<\/p>\n

| 12 | Beckham | 33 | police |<\/p>\n

+—-+———+—–+————+<\/p>\n

7 rows in set (0.00 sec)<\/p>\n

\u66f4\u65b0\u8868\u4e2d\u6307\u5b9a\u5b57\u6bb5\uff1a<\/strong>\u00a0\u4fee\u6539person\u8868\u4e2d\u6570\u636e,\u5c06id=11\u7684name\u5b57\u6bb5\u7684\u503c\u6539\u4e3axxxx,age\u5b57\u6bb5\u6539\u4e3a200,SQL\u8bed\u53e5\u5982\u4e0b:<\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+————+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+————+<\/p>\n

| 1 | LyShark | 22 | Lawyer |<\/p>\n

| 2 | Willam | 18 | sports man |<\/p>\n

| 3 | Evans | 27 | secretary |<\/p>\n

| 4 | Dale | 22 | cook |<\/p>\n

| 5 | Edison | 28 | singer |<\/p>\n

| 11 | harry | 20 | student |<\/p>\n

| 12 | Beckham | 33 | police |<\/p>\n

+—-+———+—–+————+<\/p>\n

7 rows in set (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> update person set age=200,name=’xxxx’ where id=11; #\u66f4\u65b0\u5355\u4e2a\u5b57\u6bb5<\/p>\n

Query OK, 1 row affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+————+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+————+<\/p>\n

| 1 | LyShark | 22 | Lawyer |<\/p>\n

| 2 | Willam | 18 | sports man |<\/p>\n

| 3 | Evans | 27 | secretary |<\/p>\n

| 4 | Dale | 22 | cook |<\/p>\n

| 5 | Edison | 28 | singer |<\/p>\n

| 11 | xxxx | 200 | student |<\/p>\n

| 12 | Beckham | 33 | police |<\/p>\n

+—-+———+—–+————+<\/p>\n

7 rows in set (0.00 sec)<\/p>\n

\u66f4\u65b0\u8868\u7684\u4e00\u4e2a\u8303\u56f4\uff1a<\/strong>\u00a0\u66f4\u65b0person\u8868\u4e2d\u7684\u8bb0\u5f55,\u5c061-12\u7684info\u5b57\u6bb5\u5168\u90e8\u6539\u4e3alyshark blog,SQL\u8bed\u53e5\u5982\u4e0b:<\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+————+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+————+<\/p>\n

| 1 | LyShark | 22 | Lawyer |<\/p>\n

| 2 | Willam | 18 | sports man |<\/p>\n

| 3 | Evans | 27 | secretary |<\/p>\n

| 4 | Dale | 22 | cook |<\/p>\n

| 5 | Edison | 28 | singer |<\/p>\n

| 11 | xxxx | 200 | student |<\/p>\n

| 12 | Beckham | 33 | police |<\/p>\n

+—-+———+—–+————+<\/p>\n

7 rows in set (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> update person set info=’lyshark blog’ where age between 1 and 200; #\u6307\u5b9a\u4fee\u6539\u7684\u5b57\u6bb5<\/p>\n

Query OK, 7 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+————–+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+————–+<\/p>\n

| 1 | LyShark | 22 | lyshark blog |<\/p>\n

| 2 | Willam | 18 | lyshark blog |<\/p>\n

| 3 | Evans | 27 | lyshark blog |<\/p>\n

| 4 | Dale | 22 | lyshark blog |<\/p>\n

| 5 | Edison | 28 | lyshark blog |<\/p>\n

| 11 | xxxx | 200 | lyshark blog |<\/p>\n

| 12 | Beckham | 33 | lyshark blog |<\/p>\n

+—-+———+—–+————–+<\/p>\n

7 rows in set (0.00 sec)<\/p>\n

\u5220\u9664\u8868\u4e2d\u6307\u5b9a\u8bb0\u5f55\uff1a<\/strong>\u00a0\u901a\u8fc7id\u53f7,\u5220\u9664\u8868\u4e2d\u6307\u5b9a\u5217,\u6b64\u5904\u5220\u9664\u7b2cid=12\u53f7,\u8fd9\u6761\u8bb0\u5f55,SQL\u8bed\u53e5\u5982\u4e0b:<\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+————–+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+————–+<\/p>\n

| 1 | LyShark | 22 | lyshark blog |<\/p>\n

| 2 | Willam | 18 | lyshark blog |<\/p>\n

| 3 | Evans | 27 | lyshark blog |<\/p>\n

| 4 | Dale | 22 | lyshark blog |<\/p>\n

| 5 | Edison | 28 | lyshark blog |<\/p>\n

| 11 | xxxx | 200 | lyshark blog |<\/p>\n

| 12 | Beckham | 33 | lyshark blog |<\/p>\n

+—-+———+—–+————–+<\/p>\n

7 rows in set (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> delete from person where id=12; #\u901a\u8fc7id\u53f7\uff0c\u5220\u9664\u8868\u4e2d\u6307\u5b9a\u5217<\/p>\n

Query OK, 1 row affected (0.05 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+————–+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+————–+<\/p>\n

| 1 | LyShark | 22 | lyshark blog |<\/p>\n

| 2 | Willam | 18 | lyshark blog |<\/p>\n

| 3 | Evans | 27 | lyshark blog |<\/p>\n

| 4 | Dale | 22 | lyshark blog |<\/p>\n

| 5 | Edison | 28 | lyshark blog |<\/p>\n

| 11 | xxxx | 200 | lyshark blog |<\/p>\n

+—-+———+—–+————–+<\/p>\n

6 rows in set (0.00 sec)<\/p>\n

\u5220\u9664\u8868\u7684\u4e00\u4e2a\u8303\u56f4\uff1a<\/strong>\u00a0\u5728person\u8868\u4e2d,\u5220\u9664age\u5b57\u6bb5\u503c\u572819-22\u7684\u8bb0\u5f55,SQL\u8bed\u53e5\u5982\u4e0b:<\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+———+—–+————–+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+———+—–+————–+<\/p>\n

| 1 | LyShark | 22 | lyshark blog |<\/p>\n

| 2 | Willam | 18 | lyshark blog |<\/p>\n

| 3 | Evans | 27 | lyshark blog |<\/p>\n

| 4 | Dale | 22 | lyshark blog |<\/p>\n

| 5 | Edison | 28 | lyshark blog |<\/p>\n

| 11 | xxxx | 200 | lyshark blog |<\/p>\n

+—-+———+—–+————–+<\/p>\n

6 rows in set (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> delete from person where age between 19 and 22; #\u6307\u5b9a\u8303\u56f4\u5220\u9664<\/p>\n

Query OK, 2 rows affected (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+——–+—–+————–+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+——–+—–+————–+<\/p>\n

| 2 | Willam | 18 | lyshark blog |<\/p>\n

| 3 | Evans | 27 | lyshark blog |<\/p>\n

| 5 | Edison | 28 | lyshark blog |<\/p>\n

| 11 | xxxx | 200 | lyshark blog |<\/p>\n

+—-+——–+—–+————–+<\/p>\n

4 rows in set (0.00 sec)<\/p>\n

\u6e05\u7a7a\u8868\u4e2d\u6240\u6709\u8bb0\u5f55\uff1a<\/strong><\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

+—-+——–+—–+————–+<\/p>\n

| id | name | age | info |<\/p>\n

+—-+——–+—–+————–+<\/p>\n

| 2 | Willam | 18 | lyshark blog |<\/p>\n

| 3 | Evans | 27 | lyshark blog |<\/p>\n

| 5 | Edison | 28 | lyshark blog |<\/p>\n

| 11 | xxxx | 200 | lyshark blog |<\/p>\n

+—-+——–+—–+————–+<\/p>\n

4 rows in set (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> delete from person; #\u6e05\u7a7a\u8868\u4e2d\u6240\u6709\u8bb0\u5f55<\/p>\n

Query OK, 4 rows affected (0.00 sec)<\/p>\n

 <\/p>\n

MariaDB [lyshark]> select * from person;<\/p>\n

Empty set (0.00 sec)<\/p>\n

 <\/p>\n

\u6570\u636e\u7c7b\u578b\u76f8\u5173<\/h2>\n

 <\/p>\n

\u25c6\u6574\u6570\u6570\u636e\u7c7b\u578b\u25c6<\/h3>\n

\u6570\u503c\u578b\u7c7b\u578b\u4e3b\u8981\u7528\u6765\u5b58\u50a8\u6570\u5b57,MySQL\u63d0\u4f9b\u4e86\u591a\u79cd\u6570\u503c\u6570\u636e\u7c7b\u578b,\u4e0d\u540c\u7684\u6570\u636e\u7c7b\u578b\u63d0\u4f9b\u4e0d\u540c\u7684\u53d6\u503c\u8303\u56f4,\u53ef\u4ee5\u5b58\u50a8\u7684\u503c\u8303\u56f4\u8d8a\u5927,\u5176\u6240\u9700\u8981\u7684\u5b58\u50a8\u7a7a\u95f4\u4e5f\u4f1a\u8d8a\u5927,MySQL\u4e3b\u8981\u63d0\u4f9b\u7684\u6574\u5f62\u6709:TINYINT,SMALLINT,MEDIUMINT,INT,BIGINT,\u6574\u6570\u7c7b\u578b\u7684\u5c5e\u6027\u5b57\u6bb5\u53ef\u4ee5\u6dfb\u52a0AUTO_INCREMENT\u81ea\u589e\u957f\u7ea6\u675f\u6761\u4ef6,\u5982\u4e0b\u8868\u6240\u793a:<\/p>\n\n\n\n\n\n\n\n\n\n
\u7c7b\u578b\u540d\u79f0<\/strong><\/th>\n\u8bf4\u660e\u4fe1\u606f<\/strong><\/th>\n\u5b58\u50a8\u5360\u6bd4<\/strong><\/th>\n<\/tr>\n<\/thead>\n
TINYINT<\/td>\n\u5f88\u5c0f\u7684\u6574\u6570<\/td>\n1\u4e2a\u5b57\u8282<\/td>\n<\/tr>\n
SMALLINT<\/td>\n\u5c0f\u7684\u6574\u6570<\/td>\n2\u4e2a\u5b57\u8282<\/td>\n<\/tr>\n
MEDIUMINT<\/td>\n\u4e2d\u7b49\u5927\u5c0f\u6574\u6570<\/td>\n3\u4e2a\u5b57\u8282<\/td>\n<\/tr>\n
INT<\/td>\n\u666e\u901a\u5927\u5c0f\u6574\u6570<\/td>\n4\u4e2a\u5b57\u8282<\/td>\n<\/tr>\n
BIGINT<\/td>\n\u5927\u6574\u6570<\/td>\n8\u4e2a\u5b57\u8282<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u4e0a\u8868\u53ef\u770b\u51fa,\u4e0d\u540c\u7c7b\u578b\u7684\u6570\u636e\u5b57\u8282\u662f\u4e0d\u540c\u7684,\u6574\u6570\u7c7b\u578b\u7684\u53d6\u503c\u8303\u56f4\u4e5f\u662f\u56fa\u5b9a\u7684,\u57fa\u672c\u4e0a\u5206\u4e3a\u6709\u7b26\u53f7\u548c\u65e0\u7b26\u53f7\u578b,\u4e0b\u8868\u5c31\u662f\u4ed6\u4eec\u7684\u76f8\u5e94\u53d6\u503c\u8303\u56f4,\u4ec5\u4f9b\u53c2\u8003:<\/p>\n\n\n\n\n\n\n\n\n\n
\u6570\u636e\u7c7b\u578b<\/strong><\/th>\n\u6709\u7b26\u53f7<\/strong><\/th>\n\u65e0\u7b26\u53f7<\/strong><\/th>\n<\/tr>\n<\/thead>\n
TINYINT<\/td>\n-128-127<\/td>\n0-255<\/td>\n<\/tr>\n
SMALLINT<\/td>\n32768-32767<\/td>\n0-65535<\/td>\n<\/tr>\n
MEDIUMINT<\/td>\n-8388608-8388607<\/td>\n0-16777215<\/td>\n<\/tr>\n
INT<\/td>\n-2147483648-2147483647<\/td>\n0-4294967295<\/td>\n<\/tr>\n
BIGINT<\/td>\n\u8fd9\u4e2a\u8303\u56f4\u4e0d\u591a\u8bf4,(\u5927)<\/td>\n0-\u65e0\u6cd5\u5f62\u5bb9\u7684\u5927<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u5b9e\u4f8b1:<\/strong>\u00a0\u521b\u5efa\u4e00\u4e2a\u6574\u6570\u7c7b\u578b\u7684\u8868.<\/p>\n

MariaDB [lyshark]> create table myint<\/p>\n

-> (<\/p>\n

-> uid int(10),<\/p>\n

-> name varchar(20)<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

\u4ee5\u4e0a\u662fuid\u5c31\u662f\u4e00\u4e2a\u6574\u6570\u7c7b\u578b\u7684\u5b57\u6bb5,\u6ce8\u610f\u540e\u9762\u7684(10)\u610f\u601d\u662f\u6307\u5b9a\u80fd\u591f\u663e\u793a\u7684\u6570\u503c\u4e2d\u6570\u5b57\u7684\u4e2a\u6570.<\/p>\n

\u5b9e\u4f8b2:<\/strong>\u00a0\u5206\u522b\u521b\u5efa\u6574\u5f62\u7684\u6570\u636e\u7c7b\u578b\u5b57\u6bb5\u770b\u770b.<\/p>\n

MariaDB [lyshark]> create table temp<\/p>\n

-> (<\/p>\n

-> a tinyint,<\/p>\n

-> b smallint,<\/p>\n

-> c mediumint,<\/p>\n

-> d int,<\/p>\n

-> e bigint<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> desc temp;<\/p>\n

+——-+————–+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+————–+——+—–+———+——-+<\/p>\n

| a | tinyint(4) | YES | | NULL | |<\/p>\n

| b | smallint(6) | YES | | NULL | |<\/p>\n

| c | mediumint(9) | YES | | NULL | |<\/p>\n

| d | int(11) | YES | | NULL | |<\/p>\n

| e | bigint(20) | YES | | NULL | |<\/p>\n

+——-+————–+——+—–+———+——-+<\/p>\n

5 rows in set (0.00 sec)<\/p>\n

 <\/p>\n

\u25c6\u6d6e\u70b9\u6570\u548c\u5b9a\u70b9\u6570\u25c6<\/h3>\n

\u5728MySQL\u4e2d\u6d6e\u70b9\u6570\u548c\u5b9a\u70b9\u6570\u90fd\u662f\u7528\u6765\u8868\u793a\u5c0f\u6570\u7684,\u6d6e\u70b9\u6570\u7c7b\u578b\u6709\u4e24\u79cd:\u5355\u7cbe\u5ea6\u6d6e\u70b9\u6570(FLOAT)\u548c\u53cc\u7cbe\u5ea6\u6d6e\u70b9\u6570(DOUBLE),\u5b9a\u70b9\u7c7b\u578b\u7684\u8bdd\u53ea\u6709\u4e00\u79cd(DECIMAL),\u4e0b\u8868\u662f\u8fd9\u51e0\u4e2a\u6570\u503c\u7684\u8bf4\u660e\u4fe1\u606f:<\/p>\n\n\n\n\n\n\n\n
\u7c7b\u578b\u540d\u79f0<\/strong><\/th>\n\u8bf4\u660e\u4fe1\u606f<\/strong><\/th>\n\u5b58\u50a8\u5360\u6bd4<\/strong><\/th>\n<\/tr>\n<\/thead>\n
FLOAT<\/td>\n\u5355\u7cbe\u5ea6\u6d6e\u70b9\u6570<\/td>\n4\u4e2a\u5b57\u8282<\/td>\n<\/tr>\n
DOUBLE<\/td>\n\u53cc\u7cbe\u5ea6\u6d6e\u70b9\u6570<\/td>\n8\u4e2a\u5b57\u8282<\/td>\n<\/tr>\n
DECIMAL<\/td>\n\u538b\u7f29\u7684\u5b9a\u70b9\u6570<\/td>\nM+2\u4e2a\u5b57\u8282<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u5b9e\u4f8b:<\/strong>\u00a0\u521b\u5efatemp\u8868,\u5176\u4e2d\u5b57\u6bb5x,y,z\u6570\u636e\u7c7b\u578b\u5206\u522b\u662f\u00a0float(5.1) double(5.1) decimal(5.1)\u5e76\u5411\u8868\u4e2d\u63d2\u5165\u4e00\u4e9b\u6570\u636e.<\/p>\n

MariaDB [lyshark]> create table temp<\/p>\n

-> (<\/p>\n

-> x float(5,1),<\/p>\n

-> y double(5,1),<\/p>\n

-> z decimal(5,1)<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

\u5411\u8868\u4e2d\u63d2\u5165\u6570\u636e\uff0c\u5e76\u67e5\u770b\u7ed3\u679c,MySQL\u9ed8\u8ba4\u81ea\u52a8\u622a\u65ad\u5c0f\u6570\u70b9\u540e\u9762\u7684\u6570\u636e,\u5177\u4f53\u622a\u65ad\u4f4d\u6570\u7531\u8ba1\u7b97\u673a\u786c\u4ef6\u548c\u64cd\u4f5c\u7cfb\u7edf\u51b3\u5b9a.<\/p>\n

MariaDB [lyshark]> insert into temp values(5.12,5.22,5.123);<\/p>\n

Query OK, 1 row affected, 1 warning (0.01 sec)<\/p>\n

MariaDB [lyshark]> select * from temp1;<\/p>\n

+——+——+——+<\/p>\n

| x | y | z |<\/p>\n

+——+——+——+<\/p>\n

| 5.1 | 5.2 | 5.1 |<\/p>\n

+——+——+——+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]><\/p>\n

 <\/p>\n

\u25c6\u65e5\u671f\u4e0e\u65f6\u95f4\u7c7b\u578b\u25c6<\/h3>\n

MySQL\u4e2d\u6709\u591a\u79cd\u8868\u793a\u65e5\u671f\u7684\u6570\u636e\u7c7b\u578b,\u4e3b\u8981\u6709LDATETIME\u3001DATE\u3001TIME\u548cYEAR.\u4f8b\u5982,\u5f53\u53ea\u8bb0\u5f55\u5e74\u4fe1\u606f\u7684\u65f6\u5019,\u53ef\u4ee5\u53ea\u4f7f\u7528 YEAR\u7c7b\u578b\u800c\u6ca1\u6709\u5fc5\u8981\u4f7f\u7528DATE,\u6bcf\u4e00\u4e2a\u7c7b\u578b\u90fd\u6709\u5408\u6cd5\u7684\u53d6\u503c\u8303\u56f4,\u5f53\u6307\u5b9a\u786e\u5b9e\u4e0d\u5408\u6cd5\u7684\u503c\u65f6\u7cfb\u7edf\u5c06”0″\u503c\u63d2\u5165\u5230\u6570\u636e\u5e93\u4e2d,\u4e0b\u9762\u5148\u6765\u770b\u4e00\u4e0b\u4ed6\u7684\u7c7b\u578b\u8bf4\u660e\u5427:<\/p>\n\n\n\n\n\n\n\n\n\n
\u7c7b\u578b\u540d\u79f0<\/strong><\/th>\n\u65e5\u671f\u683c\u5f0f<\/strong><\/th>\n\u65e5\u671f\u8303\u56f4<\/strong><\/th>\n\u5b58\u50a8\u9700\u6c42<\/strong><\/th>\n<\/tr>\n<\/thead>\n
YEAR<\/td>\nYYYY<\/td>\n1901-2155<\/td>\n1\u5b57\u8282<\/td>\n<\/tr>\n
TIME<\/td>\nHH:MM:SS<\/td>\n-838:59:59-838:59:59<\/td>\n3\u5b57\u8282<\/td>\n<\/tr>\n
DATE<\/td>\nYYYY-MM-DD<\/td>\n1000-01-01-9999-12-3<\/td>\n3\u5b57\u8282<\/td>\n<\/tr>\n
DATETIME<\/td>\nYYYY-MM-DD HH:MM:SS<\/td>\n1000-01-01 00:00:00-9999:12-31 23:59:59<\/td>\n8\u5b57\u8282<\/td>\n<\/tr>\n
TIMESTAMP<\/td>\nYYYY-MM-DD HH:MM:SS<\/td>\n1970-01-01 00:00:01 UTC-2038-01-19 03:14:07 UTC<\/td>\n4\u5b57\u8282<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

YEAR\u7c7b\u578b: \u4e3b\u8981\u7528\u4e8e\u5b58\u50a8\u4e00\u4e2a\u5e74\u4efd,\u4f8b\u5982\uff1a1997 2018<\/strong><\/p>\n

1.\u521b\u5efatemp\u8868,\u5b9a\u4e49\u6570\u636e\u7c7b\u578b\u4e3ayear\u7684\u5b57\u6bb5x,\u5e76\u5411\u8868\u4e2d\u63d2\u5165\u6570\u636e.<\/p>\n

MariaDB [lyshark]> create table temp(x year); #\u521b\u5efa\u4e00\u4e2ayear\u7c7b\u578b\u7684\u5b57\u6bb5<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> desc temp;<\/p>\n

+——-+———+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+———+——+—–+———+——-+<\/p>\n

| x | year(4) | YES | | NULL | |<\/p>\n

+——-+———+——+—–+———+——-+<\/p>\n

1 row in set (0.01 sec)<\/p>\n

MariaDB [lyshark]> insert into temp values(2018),(“2020”); #\u63d2\u5165\u4e00\u4e9b\u6570\u636e\uff1a\u6ce8\u610f\u5fc5\u987b\u662f1901-2155\u4e4b\u95f4\u7684\u6570<\/p>\n

Query OK, 2 rows affected (0.00 sec)<\/p>\n

Records: 2 Duplicates: 0 Warnings: 0<\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+——+<\/p>\n

| x |<\/p>\n

+——+<\/p>\n

| 2018 |<\/p>\n

| 2020 |<\/p>\n

+——+<\/p>\n

2 rows in set (0.00 sec)<\/p>\n

TIME\u7c7b\u578b:\u4e3b\u8981\u7528\u4e8e\u5b58\u50a8\u65f6\u95f4,\u4f8b\u5982\uff1a12:12:21<\/strong><\/p>\n

1.\u521b\u5efatemp1\u8868,\u5b9a\u4e49\u6570\u636e\u7c7b\u578b\u4e3atime\u7684\u5b57\u6bb5x,\u5e76\u5411\u8868\u4e2d\u63d2\u5165\u6570\u636e.<\/p>\n

MariaDB [lyshark]> create table temp1( #\u521b\u5efa\u4e00\u4e2atime\u7c7b\u578b\u7684\u5b57\u6bb5<\/p>\n

-> x time<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> desc temp1;<\/p>\n

+——-+——+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+——+——+—–+———+——-+<\/p>\n

| x | time | YES | | NULL | |<\/p>\n

+——-+——+——+—–+———+——-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> insert into temp1 values(’11:22:05′),(’23:23′),(’20’); #\u5206\u522b\u63d2\u5165\u6570\u636e\uff1a\u6ce8\u610f\uff08%HH-%MM-%SS\uff09<\/p>\n

Query OK, 3 rows affected (0.00 sec)<\/p>\n

Records: 3 Duplicates: 0 Warnings: 0<\/p>\n

MariaDB [lyshark]> select * from temp1;<\/p>\n

+———-+<\/p>\n

| x |<\/p>\n

+———-+<\/p>\n

| 11:22:05 |<\/p>\n

| 23:23:00 |<\/p>\n

| 00:00:20 |<\/p>\n

+———-+<\/p>\n

3 rows in set (0.00 sec)<\/p>\n

2.\u5f53\u7136\u5566\u6211\u4eec\u53ef\u4ee5\u7b80\u5199\u7701\u7565\u5192\u53f7.<\/p>\n

MariaDB [lyshark]> create table temp1(x time);<\/p>\n

Query OK, 0 rows affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> insert into temp1 values(‘102231’);<\/p>\n

Query OK, 1 row affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> select * from temp1;<\/p>\n

+———-+<\/p>\n

| x |<\/p>\n

+———-+<\/p>\n

| 10:22:31 |<\/p>\n

+———-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

3.\u5411temp\u8868\u4e2d\u7684x\u5b57\u6bb5\u63d2\u5165\u5f53\u524d\u7cfb\u7edf\u8fd0\u884c\u65f6\u95f4,\u901a\u8fc7\u51fd\u6570(CURRENT_TIME),(NOW()\u53d6\u51fa.<\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

Empty set (0.00 sec)<\/p>\n

MariaDB [lyshark]> insert into temp values (CURRENT_TIME),(NOW());<\/p>\n

Query OK, 2 rows affected, 1 warning (0.00 sec)<\/p>\n

Records: 2 Duplicates: 0 Warnings: 1<\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+———-+<\/p>\n

| x |<\/p>\n

+———-+<\/p>\n

| 21:27:43 |<\/p>\n

| 21:27:43 |<\/p>\n

+———-+<\/p>\n

2 rows in set (0.00 sec)<\/p>\n

DATE\u7c7b\u578b:Date\u7c7b\u578b\u4e3b\u8981\u7528\u4e8e\u5b58\u50a8\u5e74\u6708\u65e5,\u4f8b\u5982\uff1a1997-10-05<\/strong><\/p>\n

1.\u521b\u5efatemp\u8868,\u8868\u4e2d\u662fdate\u7c7b\u578b\u7684x\u5b57\u6bb5,\u5e76\u63d2\u5165\u4e00\u6761\u6570\u636e.<\/p>\n

MariaDB [lyshark]> create table temp(x date); #\u521b\u5efa\u4e00\u4e2adate\u7c7b\u578b\u7684\u5b57\u6bb5<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> desc temp;<\/p>\n

+——-+——+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+——+——+—–+———+——-+<\/p>\n

| x | date | YES | | NULL | |<\/p>\n

+——-+——+——+—–+———+——-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> insert into temp values(‘1997-10-05’),(‘20180523’); #\u63d2\u5165\u4e00\u4e9b\u6570\u636e<\/p>\n

Query OK, 2 rows affected (0.00 sec)<\/p>\n

Records: 2 Duplicates: 0 Warnings: 0<\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+————+<\/p>\n

| x |<\/p>\n

+————+<\/p>\n

| 1997-10-05 |<\/p>\n

| 2018-05-23 |<\/p>\n

+————+<\/p>\n

2 rows in set (0.00 sec)<\/p>\n

2.\u5411temp\u8868\u4e2d\u63d2\u5165\u7cfb\u7edf\u5f53\u524d\u65e5\u671f,\u901a\u8fc7\u51fd\u6570(CURRENT_DATE()),(NOW())\u53d6\u51fa\u7cfb\u7edf\u65e5\u671f.<\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+————+<\/p>\n

| x |<\/p>\n

+————+<\/p>\n

| 1997-10-05 |<\/p>\n

| 2018-05-23 |<\/p>\n

+————+<\/p>\n

2 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> insert into temp values(CURRENT_DATE()),(NOW()); #\u53d6\u51fa\u7cfb\u7edf\u5f53\u524d\u65e5\u671f\u5e76\u63d2\u5165<\/p>\n

Query OK, 2 rows affected, 1 warning (0.00 sec)<\/p>\n

Records: 2 Duplicates: 0 Warnings: 1<\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+————+<\/p>\n

| x |<\/p>\n

+————+<\/p>\n

| 1997-10-05 |<\/p>\n

| 2018-05-23 |<\/p>\n

| 2018-06-16 |<\/p>\n

| 2018-06-16 |<\/p>\n

+————+<\/p>\n

4 rows in set (0.00 sec)<\/p>\n

DATATIME:DateTime\u7c7b\u578b\u7528\u4e8e\u5b58\u50a8\u65e5\u671f\u548c\u65f6\u95f4,\u4f8b\u5982\uff1a2018-01-24 22:12:24<\/strong><\/p>\n

1.\u521b\u5efatemp\u8868dt\u5b57\u6bb5\u7c7b\u578b\u4e3adatetime,\u5e76\u63d2\u5165\u4e00\u6761\u6570\u636e.<\/p>\n

MariaDB [lyshark]> create table temp(dt datetime);<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> desc temp;<\/p>\n

+——-+———-+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+———-+——+—–+———+——-+<\/p>\n

| dt | datetime | YES | | NULL | |<\/p>\n

+——-+———-+——+—–+———+——-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> insert into temp values(‘1997-05-10 10:22:14’),(‘20180616220101’); #\u63d2\u5165\u65e5\u671f\u65f6\u95f4<\/p>\n

Query OK, 2 rows affected (0.00 sec)<\/p>\n

Records: 2 Duplicates: 0 Warnings: 0<\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+———————+<\/p>\n

| dt |<\/p>\n

+———————+<\/p>\n

| 1997-05-10 10:22:14 |<\/p>\n

| 2018-06-16 22:01:01 |<\/p>\n

+———————+<\/p>\n

2 rows in set (0.00 sec)<\/p>\n

2.\u53d6\u7cfb\u7edf\u5f53\u524d\u65e5\u671f\u5e76\u63d2\u5165temp\u8868\u7684dt\u5b57\u6bb5.<\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+———————+<\/p>\n

| dt |<\/p>\n

+———————+<\/p>\n

| 1997-05-10 10:22:14 |<\/p>\n

| 2018-06-16 22:01:01 |<\/p>\n

+———————+<\/p>\n

2 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> insert into temp values(now()); #\u53d6\u7cfb\u7edf\u65e5\u671f\u63d2\u5165temp\u8868\u7684dt\u5b57\u6bb5<\/p>\n

Query OK, 1 row affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+———————+<\/p>\n

| dt |<\/p>\n

+———————+<\/p>\n

| 1997-05-10 10:22:14 |<\/p>\n

| 2018-06-16 22:01:01 |<\/p>\n

| 2018-06-16 22:03:39 |<\/p>\n

+———————+<\/p>\n

3 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]><\/p>\n

TIMESTAMP\u7c7b\u578b:TimeStamp\u4e0eDateTime\u76f8\u540c,\u4f46\u662fTimeStamp\u662f\u4f7f\u7528\u7684UTC(\u4e16\u754c\u6807\u51c6\u65f6\u95f4)<\/strong><\/p>\n

1.\u521b\u5efatemp\u8868\u5e76\u63d2\u5165timestamp\u7c7b\u578b\u7684x\u5b57\u6bb5,\u63d2\u5165\u4e00\u6761\u6570\u636e.<\/p>\n

MariaDB [lyshark]> create table temp(x timestamp); #\u521b\u5efa\u4e00\u4e2atimestamp\u7c7b\u578b\u7684\u5b57\u6bb5<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> desc temp;<\/p>\n

+——-+———–+——+—–+——————-+—————————–+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+———–+——+—–+——————-+—————————–+<\/p>\n

| x | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |<\/p>\n

+——-+———–+——+—–+——————-+—————————–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> insert into temp values(‘2018-06-16 22:24:00′); #\u63d2\u5165\u4e00\u6761\u65f6\u95f4\u8bb0\u5f55<\/p>\n

Query OK, 1 row affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> select *from temp;<\/p>\n

+———————+<\/p>\n

| x |<\/p>\n

+———————+<\/p>\n

| 2018-06-16 22:24:00 |<\/p>\n

+———————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> set time_zone=’+12:00’ #\u5c06\u65f6\u95f4\u4e0a\u8c0312\u5c0f\u65f6<\/p>\n

-> ;<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> select * from temp; #\u518d\u6b21\u67e5\u8be2\u5df2\u7ecf\u662f\u7b2c\u4e8c\u5929\u4e86<\/p>\n

+———————+<\/p>\n

| x |<\/p>\n

+———————+<\/p>\n

| 2018-06-17 02:24:00 |<\/p>\n

+———————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

 <\/p>\n

\u25c6\u6587\u672c\u5b57\u7b26\u4e32\u7c7b\u578b\u25c6<\/h3>\n

\u5b57\u7b26\u4e32\u7c7b\u578b\u7528\u6765\u5b58\u50a8\u5b57\u7b26\u4e32\u6570\u636e,\u9664\u4e86\u53ef\u4ee5\u5b58\u50a8\u5b57\u7b26\u4e32\u6570\u636e\u4e4b\u5916,\u8fd8\u53ef\u4ee5\u5b58\u50a8\u5176\u4ed6\u6570\u636e,\u6bd4\u5982\u56fe\u7247\u548c\u58f0\u97f3\u7684\u4e8c\u8fdb\u5236\u6570\u636e.MySQL\u652f\u6301\u4e24\u7c7b\u5b57\u7b26\u578b\u6570\u636e:\u6587\u672c\u5b57\u7b26\u4e32\u548c\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32,\u672c\u5c0f\u8282\u4e3b\u8981\u4ecb\u7ecd\u6587\u672c\u5b57\u7b26\u4e32\u7c7b\u578b,\u6587\u672c\u5b57\u7b26\u4e32\u53ef\u4ee5\u8fdb\u884c\u533a\u5206\u6216\u8005\u4e0d\u533a\u5206\u5927\u5c0f\u5199\u7684\u4e32\u6bd4\u8f83,\u53e6\u5916\u8fd8\u53ef\u4ee5\u8fdb\u884c\u6a21\u5f0f\u5339\u914d\u67e5\u627e.MysQL\u4e2d\u6587\u672c\u5b57\u7b26\u4e32\u7c7b\u578b\u6307CHAR,VARCHAR,TEXT,ENUM\u548cSET,\u5982\u4e0b\u8868\u6240\u793a.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n
\u7c7b\u578b\u540d\u79f0<\/strong><\/th>\n\u8bf4\u660e\u4fe1\u606f<\/strong><\/th>\n\u5b58\u50a8\u9700\u6c42<\/strong><\/th>\n<\/tr>\n<\/thead>\n
CHAR<\/td>\n\u56fa\u5b9a\u957f\u5ea6\u975e\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32<\/td>\nM\u5b57\u8282,1<=M<=255<\/td>\n<\/tr>\n
VARCHAR<\/td>\n\u53d8\u957f\u975e\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32<\/td>\nL+1\u5b57\u8282<\/td>\n<\/tr>\n
TIMYTEXT<\/td>\n\u975e\u5e38\u5c0f\u7684\u975e\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32<\/td>\nL+1\u5b57\u8282<\/td>\n<\/tr>\n
TEXT<\/td>\n\u5c0f\u7684\u975e\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32<\/td>\nL+2\u5b57\u8282<\/td>\n<\/tr>\n
MEDIUMTEXT<\/td>\n\u4e2d\u7b49\u975e\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32<\/td>\nL+3\u5b57\u8282<\/td>\n<\/tr>\n
LONGTEXT<\/td>\n\u5927\u7684\u975e\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32<\/td>\nL+4\u5b57\u8282<\/td>\n<\/tr>\n
ENUM<\/td>\n\u679a\u4e3e\u7c7b\u578b<\/td>\nl\u62162\u4e2a\u5b57\u8282<\/td>\n<\/tr>\n
SET<\/td>\nSET\u6210\u5458\u7c7b\u578b<\/td>\n1,2,3,4\u62168\u4e2a\u5b57\u8282<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

CHAR\u548cVARCHAR:\u5b9a\u957f\u548c\u4e0d\u5b9a\u957f\u5b57\u7b26\u4e32\u7c7b\u578b<\/strong><\/p>\n

CHAR\u548cVARCHAR\u7684\u957f\u5ea6\u533a\u522b:<\/p>\n

\u25cf CHAR\u662f\u4e00\u79cd\u5b9a\u957f\u5b57\u7b26\u4e32,\u5b83\u7684\u957f\u5ea6\u5728\u521d\u59cb\u5316\u65f6\u5c31\u88ab\u56fa\u5b9a\u6bd4\u5982\u8bf4\uff1achar(10)\u5219\u56fa\u5b9a\u5206\u914d10\u4e2a\u5b57\u7b26\u7684\u957f\u5ea6,\u5982\u679c\u4f7f\u7528\u4e86CHAR\u7c7b\u578b,\u4e0d\u8bba\u4f60\u7684\u6570\u636e\u586b\u5145\u591a\u5c11\u90fd\u4f1a\u6d88\u80174\u5b57\u8282\u5b58\u50a8\u7a7a\u95f4.
\n\u25cf VARCHAR\u662f\u4e00\u79cd\u4e0d\u5b9a\u957f\u5b57\u7b26\u4e32,\u5b83\u7684\u957f\u5ea6\u53d6\u51b3\u4e8e\u4f60\u8f93\u5165\u7684\u5b57\u7b26\u6570,\u4f7f\u7528VARCHAR\u7684\u8bdd,\u5b83\u4f1a\u52a8\u6001\u7684\u5206\u914d\u7a7a\u95f4\u5927\u5c0f,\u4f46\u6700\u5927\u4e5f\u4e0d\u80fd\u8d85\u8fc7\u5b9a\u4e49\u7684\u957f\u5ea6<\/p>\n

1.\u5b9a\u4e49\u4e00\u4e2atemp\u8868,\u91cc\u9762\u6709\u4e24\u4e2a\u5b57\u6bb5\u5206\u522b\u662fch,vch\u7c7b\u578b\u662fchar(4)\u548cvarchar(4)\u63d2\u5165\u6570\u636e\u67e5\u770b\u533a\u522b.<\/p>\n

MariaDB [lyshark]> create table temp<\/p>\n

-> (<\/p>\n

-> ch char(4),<\/p>\n

-> vch varchar(4)<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> desc temp;<\/p>\n

+——-+————+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+————+——+—–+———+——-+<\/p>\n

| ch | char(4) | YES | | NULL | |<\/p>\n

| vch | varchar(4) | YES | | NULL | |<\/p>\n

+——-+————+——+—–+———+——-+<\/p>\n

2 rows in set (0.01 sec)<\/p>\n

MariaDB [lyshark]> insert into temp values(‘xy ‘,’xy ‘);<\/p>\n

Query OK, 1 row affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> select *from temp;<\/p>\n

+——+——+<\/p>\n

| ch | vch |<\/p>\n

+——+——+<\/p>\n

| xy | xy |<\/p>\n

+——+——+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

TEXT\u7c7b\u578b:\u7528\u4e8e\u4fdd\u5b58\u975e\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32,\u5982\u6587\u7ae0\u5185\u5bb9\u8bc4\u8bba\u5185\u5bb9\u7b49,\u5f53\u4fdd\u5b58\u6216\u67e5\u8be2text\u5217\u7684\u503c\u65f6,\u4e0d\u5220\u9664\u5c3e\u90e8\u7a7a\u683c.<\/strong><\/p>\n

\u5173\u4e8eTEXT\u7c7b\u578b\u7684\u53d6\u503c\u8303\u56f4:<\/p>\n

\u25cf TINYTEXT \u6700\u5927\u957f\u5ea6\u4e3a255(2^8-1)\u5b57\u7b26\u7684TEXT\u5217.
\n\u25cf TEXT \u6700\u5927\u957f\u5ea6\u4e3a65535(2^16-1)\u5b57\u7b26\u7684TEXT\u5217.
\n\u25cf MEDIUMTEXT \u6700\u5927\u957f\u5ea6\u4e3a16777215(2^24-1)\u5b57\u7b26\u7684TEXT\u5217.
\n\u25cf LONGTEXT \u6700\u5927\u957f\u5ea6\u4e3a4294967295\u5b57\u7b26\u7684TEXT\u5217.<\/p>\n

1.\u521b\u5efa\u4e00\u4e2a\u8868temp1,\u5e76\u521b\u5efatext\u5b57\u6bb5,\u5199\u5165\u4e00\u6bb5\u8bdd\u770b\u770b.<\/p>\n

MariaDB [lyshark]> create table temp1(x text);<\/p>\n

Query OK, 0 rows affected (0.02 sec)<\/p>\n

MariaDB [lyshark]> desc temp1;<\/p>\n

+——-+——+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+——+——+—–+———+——-+<\/p>\n

| x | text | YES | | NULL | |<\/p>\n

+——-+——+——+—–+———+——-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> insert into temp1 values(‘hello lyshark’)<\/p>\n

-> ;<\/p>\n

Query OK, 1 row affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> select * from temp1;<\/p>\n

+—————+<\/p>\n

| x |<\/p>\n

+—————+<\/p>\n

| hello lyshark |<\/p>\n

+—————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

ENUM\u679a\u4e3e\u7c7b\u578b:enum\u7684\u503c\u6839\u636e\u5217\u7d22\u5f15\u987a\u5e8f\u6392\u5217,\u5e76\u4e14\u7a7a\u5b57\u7b26\u4e32\u6392\u5728\u975e\u7a7a\u5b57\u7b26\u4e32\u524d,NULL\u503c\u6392\u5728\u5176\u4ed6\u6240\u6709\u7684\u679a\u4e3e\u503c\u524d\u9762<\/strong><\/p>\n

1.\u6765\u770b\u4e00\u4e2a\u679a\u4e3e\u7684\u5c0f\u4f8b\u5b50,\u6ce8\u610f:\u679a\u4e3e\u9ed8\u8ba4\u6807\u53f7\u4ece1\u5f00\u59cb.<\/p>\n

MariaDB [lyshark]> create table temp2(enm enum(‘first’,’second’,’thire’));<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> desc temp2;<\/p>\n

+——-+——————————–+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+——————————–+——+—–+———+——-+<\/p>\n

| enm | enum(‘first’,’second’,’thire’) | YES | | NULL | |<\/p>\n

+——-+——————————–+——+—–+———+——-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> insert into temp2 values(‘1’),(‘2’),(‘3’),(NULL);<\/p>\n

Query OK, 4 rows affected (0.00 sec)<\/p>\n

Records: 4 Duplicates: 0 Warnings: 0<\/p>\n

MariaDB [lyshark]> select * from temp2;<\/p>\n

+——–+<\/p>\n

| enm |<\/p>\n

+——–+<\/p>\n

| first |<\/p>\n

| second |<\/p>\n

| thire |<\/p>\n

| NULL |<\/p>\n

+——–+<\/p>\n

4 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]><\/p>\n

set\u96c6\u5408:\u4f46\u5728\u58f0\u660e\u6210\u96c6\u5408\u65f6,\u5176\u53d6\u503c\u5c31\u5df2\u7ecf\u56fa\u5b9a\u4e86<\/strong><\/p>\n

MariaDB [lyshark]> create table temp3(s set(‘a’,’b’,’c’,’d’)); #\u9996\u5148\u5b9a\u4e49\u4e86\u4e00\u4e2a\u96c6\u5408\uff0c\u5143\u7d20\u6709abcd<\/p>\n

Query OK, 0 rows affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> desc temp3;<\/p>\n

+——-+———————-+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+———————-+——+—–+———+——-+<\/p>\n

| s | set(‘a’,’b’,’c’,’d’) | YES | | NULL | |<\/p>\n

+——-+———————-+——+—–+———+——-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]><\/p>\n

MariaDB [lyshark]> insert into temp3 values(‘a’),(‘a,b,c’),(‘a,b,c,d’); #\u5206\u522b\u63d2\u51653\u4e2a\u4e0d\u540c\u7684\u96c6\u5408\uff0c\u770b\u770b<\/p>\n

Query OK, 3 rows affected (0.00 sec)<\/p>\n

Records: 3 Duplicates: 0 Warnings: 0<\/p>\n

MariaDB [lyshark]> select * from temp3;<\/p>\n

+———+<\/p>\n

| s |<\/p>\n

+———+<\/p>\n

| a |<\/p>\n

| a,b,c |<\/p>\n

| a,b,c,d |<\/p>\n

+———+<\/p>\n

3 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> insert into temp3 values(‘a,’f”); #\u5728\u63d2\u5165f\u65f6\u62a5\u9519\uff0c\u56e0\u4e3a\u96c6\u5408\u4e2d\u5b9a\u4e49\u662f\u6ca1\u6709f<\/p>\n

ERROR 1064 (42000): You have an error in your SQL syntax;<\/p>\n

 <\/p>\n

\u25c6\u4e8c\u8fdb\u5236\u5b57\u4e32\u7c7b\u578b\u25c6<\/h3>\n

\u5728MySQL\u4e2d\u7684\u4e8c\u8fdb\u5236\u6570\u636e\u7c7b\u578b\u6709:BIT\u3001BINARY\u3001VARBINARY\u3001TINYBLOB\u3001BLOB\u3001MEDIUMBLOB,LONGBLOB,\u8001\u6837\u5b50,\u770b\u4e0b\u9762\u7684\u8868\u683c,\u5c31\u6e05\u6670\u5566.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n
\u7c7b\u578b\u540d\u79f0<\/strong><\/th>\n\u8bf4\u660e\u4fe1\u606f<\/strong><\/th>\n\u5b58\u50a8\u9700\u6c42<\/strong><\/th>\n<\/tr>\n<\/thead>\n
BIT<\/td>\n\u4f4d\u5b57\u6bb5\u7c7b\u578b<\/td>\n(M+7\/8)\u4e2a\u5b57\u8282<\/td>\n<\/tr>\n
BINARY<\/td>\n\u56fa\u5b9a\u957f\u5ea6\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32<\/td>\nM\u4e2a\u5b57\u8282<\/td>\n<\/tr>\n
VARBINARY<\/td>\n\u53ef\u53d8\u957f\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32<\/td>\nM+1\u5b57\u8282<\/td>\n<\/tr>\n
TINYBLOB<\/td>\n\u975e\u5e38\u5c0f\u7684BLOB<\/td>\nL+1\u5b57\u8282<\/td>\n<\/tr>\n
BLOB<\/td>\n\u5c0fBLOB<\/td>\nL+2\u5b57\u8282<\/td>\n<\/tr>\n
MEDIUMBLOB<\/td>\n\u4e2d\u7b49\u5927\u5c0f\u7684BLOB<\/td>\nL+3\u5b57\u8282<\/td>\n<\/tr>\n
LONGBLOB<\/td>\n\u975e\u5e38\u5927\u7684BLOB<\/td>\nL+4\u5b57\u8282<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

bit\u7c7b\u578b:\u4f4d\u5b57\u6bb5\u7c7b\u578b,\u4e5f\u5c31\u662f\u8bf4\u63d2\u5165\u7684\u6570\u636e\u4f1a\u88ab\u8f6c\u6362\u6210101011011\u8fd9\u6837\u7684\u683c\u5f0f<\/strong><\/p>\n

1.\u5b9a\u4e49\u5e76\u63d2\u5165\u6570\u636e\u6d4b\u8bd5,x+0\u8868\u793a\u5c06\u4e8c\u8fdb\u5236\u7ed3\u679c\u8f6c\u6362\u4e3a\u5bf9\u5e94\u7684\u6570\u5b57\u7684\u503c,bin()\u51fd\u6570\u5c06\u6570\u5b57\u8f6c\u6362\u4e3a2\u8fdb\u5236.<\/p>\n

MariaDB [lyshark]> create table temp5(x bit(4));<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> desc temp5;<\/p>\n

+——-+——–+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+——–+——+—–+———+——-+<\/p>\n

| x | bit(4) | YES | | NULL | |<\/p>\n

+——-+——–+——+—–+———+——-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> insert into temp5 values(100),(115),(10);<\/p>\n

Query OK, 3 rows affected, 2 warnings (0.00 sec)<\/p>\n

Records: 3 Duplicates: 0 Warnings: 2<\/p>\n

MariaDB [lyshark]> select BIN(x+0) from temp5;<\/p>\n

+———-+<\/p>\n

| BIN(x+0) |<\/p>\n

+———-+<\/p>\n

| 1111 |<\/p>\n

| 1111 |<\/p>\n

| 1010 |<\/p>\n

+———-+<\/p>\n

3 rows in set (0.00 sec)<\/p>\n

BINARY\u548cVARBINARY\u7c7b\u578b:<\/strong>\u00a0\u5b9a\u957f\u4e0e\u4e0d\u5b9a\u957f\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\u7c7b\u578b.<\/p>\n

1.binary\u7c7b\u578b\u662f\u4e00\u4e2a\u5b9a\u957f,\u4e8c\u8fdb\u5236\u5b57\u8282\u5b57\u7b26\u4e32\u7c7b\u578b,\u5728\u5b57\u6bb5\u4e0d\u8db3\u5236\u5b9a\u5b57\u8282\u662f\u4f1a\u81ea\u52a8\u5728\u540e\u9762\u586b\\0.
\n2.varbinary\u7c7b\u578b\u662f\u4e00\u4e2a\u53ef\u53d8\u957f,\u4e8c\u8fdb\u5236\u5b57\u8282\u5b57\u7b26\u4e32\u7c7b\u578b,\u800cvb\u5b57\u6bb5\u4e0d\u4f1a\u586b\u5145.<\/p>\n

\u521b\u5efa\u4e00\u4e2atemp10,\u5206\u522b\u6709\u4e24\u4e2a\u5b57\u6bb5b,vb\u7c7b\u578b\u5206\u522b\u662fbinary(3)\u548cvarbinary(30)<\/p>\n

MariaDB [lyshark]> create table temp10(<\/p>\n

-> b binary(3),<\/p>\n

-> vb varbinary(30)<\/p>\n

-> );<\/p>\n

Query OK, 0 rows affected (0.00 sec)<\/p>\n

MariaDB [lyshark]> desc temp10;<\/p>\n

+——-+—————+——+—–+———+——-+<\/p>\n

| Field | Type | Null | Key | Default | Extra |<\/p>\n

+——-+—————+——+—–+———+——-+<\/p>\n

| b | binary(3) | YES | | NULL | |<\/p>\n

| vb | varbinary(30) | YES | | NULL | |<\/p>\n

+——-+—————+——+—–+———+——-+<\/p>\n

2 rows in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> insert into temp10 values(5,5);<\/p>\n

Query OK, 1 row affected (0.01 sec)<\/p>\n

MariaDB [lyshark]> select length(b),length(vb) from temp10; #\u53ef\u4ee5\u770b\u5230b\u5360\u75283\u5b57\u8282\uff0c\u800cvb\u662f\u53ea\u5360\u75281\u5b57\u8282<\/p>\n

+———–+————+<\/p>\n

| length(b) | length(vb) |<\/p>\n

+———–+————+<\/p>\n

| 3 | 1 |<\/p>\n

+———–+————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

 <\/p>\n

\u8fd0\u7b97\u7b26\u7c7b\u578b<\/h2>\n

\u8fd0\u7b97\u7b26\u94fe\u63a5\u8868\u8fbe\u5f0f\u4e2d\u5404\u4e2a\u64cd\u4f5c\u6570,\u5176\u4f5c\u7528\u662f\u7528\u6765\u6307\u660e\u5bf9\u64cd\u4f5c\u6570\u6240\u8fdb\u884c\u7684\u8fd0\u7b97,\u8fd0\u7528\u8fd0\u7b97\u7b26\u53ef\u4ee5\u66f4\u52a0\u7075\u6d3b\u7684\u4f7f\u7528\u8868\u4e2d\u7684\u6570\u636e,\u5e38\u89c1\u7684\u8fd0\u7b97\u7b26\u6709:\u7b97\u672f\u8fd0\u7b97,\u6bd4\u8f83\u8fd0\u7b97,\u903b\u8f91\u8fd0\u7b97,\u4f4d\u8fd0\u7b97\u7b49,\u4e0b\u9762\u6211\u4eec\u5c06\u4f9d\u6b21\u4ecb\u7ecd\u8fd9\u51e0\u79cd\u8fd0\u7b97\u7b26\u7684\u8fd0\u7528.<\/p>\n

 <\/p>\n

\u25c6\u7b97\u672f\u8fd0\u7b97\u7b26\u25c6<\/h3>\n\n\n\n\n\n\n\n\n\n
\u8fd0\u7b97\u7b26<\/strong><\/th>\n\u4f5c\u7528<\/strong><\/th>\n<\/tr>\n<\/thead>\n
+<\/td>\n\u52a0\u6cd5\u8fd0\u7b97<\/td>\n<\/tr>\n
–<\/td>\n\u51cf\u6cd5\u8fd0\u7b97<\/td>\n<\/tr>\n
*<\/td>\n\u4e58\u6cd5\u8fd0\u7b97<\/td>\n<\/tr>\n
\/<\/td>\n\u9664\u6cd5\u8fd0\u7b97<\/td>\n<\/tr>\n
%<\/td>\n\u6c42\u4f59\u8fd0\u7b97<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u52a0\u6cd5\u8fd0\u7b97(+)<\/strong><\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+——+<\/p>\n

| num |<\/p>\n

+——+<\/p>\n

| 100 |<\/p>\n

+——+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> select num,num+10 from temp;<\/p>\n

+——+——–+<\/p>\n

| num | num+10 |<\/p>\n

+——+——–+<\/p>\n

| 100 | 110 |<\/p>\n

+——+——–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u51cf\u6cd5\u8fd0\u7b97(-)<\/strong><\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+——+<\/p>\n

| num |<\/p>\n

+——+<\/p>\n

| 100 |<\/p>\n

+——+<\/p>\n

1 row in set (0.01 sec)<\/p>\n

MariaDB [lyshark]> select num,num-10 from temp;<\/p>\n

+——+——–+<\/p>\n

| num | num-10 |<\/p>\n

+——+——–+<\/p>\n

| 100 | 90 |<\/p>\n

+——+——–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u4e58\u6cd5\u8fd0\u7b97(*)<\/strong><\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+——+<\/p>\n

| num |<\/p>\n

+——+<\/p>\n

| 100 |<\/p>\n

+——+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> select num,num*10 from temp;<\/p>\n

+——+——–+<\/p>\n

| num | num*10 |<\/p>\n

+——+——–+<\/p>\n

| 100 | 1000 |<\/p>\n

+——+——–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u9664\u6cd5\u8fd0\u7b97(\/)<\/strong><\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+——+<\/p>\n

| num |<\/p>\n

+——+<\/p>\n

| 100 |<\/p>\n

+——+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> select num,num\/10 from temp;<\/p>\n

+——+———+<\/p>\n

| num | num\/10 |<\/p>\n

+——+———+<\/p>\n

| 100 | 10.0000 |<\/p>\n

+——+———+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u53d6\u4f59\u6570\u8fd0\u7b97(%)<\/strong><\/p>\n

MariaDB [lyshark]> select * from temp;<\/p>\n

+——+<\/p>\n

| num |<\/p>\n

+——+<\/p>\n

| 100 |<\/p>\n

+——+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> select num,num%10 from temp;<\/p>\n

+——+——–+<\/p>\n

| num | num%10 |<\/p>\n

+——+——–+<\/p>\n

| 100 | 0 |<\/p>\n

+——+——–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

 <\/p>\n

\u25c6\u6bd4\u8f83\u8fd0\u7b97\u7b26\u25c6<\/h3>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
\u8fd0\u7b97\u7b26<\/strong><\/th>\n\u4f5c\u7528<\/strong><\/th>\n<\/tr>\n<\/thead>\n
=<\/td>\n\u7b49\u4e8e<\/td>\n<\/tr>\n
<=><\/td>\n\u5b89\u5168\u7684\u7b49\u4e8e<\/td>\n<\/tr>\n
<>(!=)<\/td>\n\u4e0d\u7b49\u4e8e<\/td>\n<\/tr>\n
<=<\/td>\n\u5c0f\u4e8e\u7b49\u4e8e<\/td>\n<\/tr>\n
>=<\/td>\n\u5927\u4e8e\u7b49\u4e8e<\/td>\n<\/tr>\n
><\/td>\n\u5927\u4e8e<\/td>\n<\/tr>\n
IS NULL<\/td>\n\u5224\u65ad\u4e00\u4e2a\u503c\u662f\u5426\u4e3aNULL<\/td>\n<\/tr>\n
IS NOT NULL<\/td>\n\u5224\u65ad\u4e00\u4e2a\u503c\u662f\u5426\u4e0d\u4e3aNULL<\/td>\n<\/tr>\n
LEAST<\/td>\n\u5728\u6709\u4e24\u4e2a\u6216\u591a\u4e2a\u53c2\u6570\u65f6,\u8fd4\u56de\u6700\u5c0f\u503c<\/td>\n<\/tr>\n
GREATEST<\/td>\n\u5f53\u6709\u4e24\u4e2a\u6216\u591a\u4e2a\u53c2\u6570\u65f6,\u8fd4\u56de\u6700\u5927\u503c<\/td>\n<\/tr>\n
BETWEEN AND<\/td>\n\u5224\u65ad\u4e00\u4e2a\u503c\u662f\u5426\u843d\u5728\u4e24\u4e2a\u503c\u4e4b\u95f4<\/td>\n<\/tr>\n
ISNULL<\/td>\n\u4e0eIS NULL\u4f5c\u7528\u76f8\u540c<\/td>\n<\/tr>\n
IN<\/td>\n\u5224\u65ad\u4e00\u4e2a\u503c\u662fIN\u5217\u8868\u4e2d\u7684\u4efb\u610f\u4e00\u4e2a\u503c<\/td>\n<\/tr>\n
NOT IN<\/td>\n\u5224\u65ad\u4e00\u4e2a\u503c\u4e0d\u662fIN\u5217\u8868\u4e2d\u7684\u4efb\u610f\u4e00\u4e2a\u503c<\/td>\n<\/tr>\n
LIKE<\/td>\n\u901a\u914d\u7b26\u5339\u914d<\/td>\n<\/tr>\n
REGEXP<\/td>\n\u6b63\u5219\u8868\u8fbe\u5f0f\u5339\u914d<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u7b49\u4e8e\u8fd0\u7b97\u7b26(=):<\/strong>\u00a0\u4f7f\u7528\u7b49\u4e8e\u8fd0\u7b97\u7b26\u8fdb\u884c\u76f8\u7b49\u5224\u65ad<\/p>\n

MariaDB [lyshark]> select 1=1 , 1=0 , ‘1’=1 , ‘0.01’=0 , ‘a’=’a’ , (1+1)=(2+2) , NULL=NULL;<\/p>\n

+—–+—–+——-+———-+———+————-+———–+<\/p>\n

| 1=1 | 1=0 | ‘1’=1 | ‘0.01’=0 | ‘a’=’a’ | (1+1)=(2+2) | NULL=NULL |<\/p>\n

+—–+—–+——-+———-+———+————-+———–+<\/p>\n

| 1 | 0 | 1 | 0 | 1 | 0 | NULL |<\/p>\n

+—–+—–+——-+———-+———+————-+———–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u5168\u7b49\u4e8e(<=>):<\/strong>\u00a0\u8fd9\u4e2a\u8fd0\u7b97\u7b26\u548c=\u529f\u80fd\u76f8\u540c,\u4f46\u662f\u5168\u7b49\u4e8e\u53ef\u4ee5\u7528\u6765\u5224\u65adNULL\u503c,\u800c\u7b49\u4e8e\u662f\u4e0d\u80fd\u7684<\/p>\n

MariaDB [lyshark]> select 1<=>0 , 1<=>1 , ‘1’<=>1 , ‘0.01’ <=> 0 , ‘a’ <=> ‘a’ , (10+10)<=>(20+20) , NULL<=>NULL ;<\/p>\n

+——-+——-+———+————–+————-+——————-+————-+<\/p>\n

| 1<=>0 | 1<=>1 | ‘1’<=>1 | ‘0.01’ <=> 0 | ‘a’ <=> ‘a’ | (10+10)<=>(20+20) | NULL<=>NULL |<\/p>\n

+——-+——-+———+————–+————-+——————-+————-+<\/p>\n

| 0 | 1 | 1 | 0 | 1 | 0 | 1 |<\/p>\n

+——-+——-+———+————–+————-+——————-+————-+<\/p>\n

row in set (0.00 sec)<\/p>\n

\u4e0d\u7b49\u4e8e(<>\u6216!=):<\/strong>\u00a0\u4fe9\u6570\u4e0d\u76f8\u7b49\u8fd4\u56de1,\u76f8\u7b49\u8fd4\u56de0<\/p>\n

MariaDB [lyshark]> select ‘lyshark’ != ‘admin’ , 1!=2 , 1 <> 1 , (10+10)<>(10+10) , NULL!=NULL;<\/p>\n

+———————-+——+——–+——————+————+<\/p>\n

| ‘lyshark’ != ‘admin’ | 1!=2 | 1 <> 1 | (10+10)<>(10+10) | NULL!=NULL |<\/p>\n

+———————-+——+——–+——————+————+<\/p>\n

| 1 | 1 | 0 | 0 | NULL |<\/p>\n

+———————-+——+——–+——————+————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u5c0f\u4e8e\u8fd0\u7b97\u7b26(<):<\/strong>\u00a0\u4e24\u6570\u76f8\u6bd4\u8f83,\u5de6\u8fb9\u5c0f\u4e8e\u53f3\u8fb9\u8fd4\u56de1,\u5426\u5219\u8fd4\u56de0<\/p>\n

MariaDB [lyshark]> select ‘xxx’ < ‘xxxx’ , 1<2 , 1<1 , 5.5<5 , (1+1)<(10-10) , NULL <NULL ;<\/p>\n

+—————-+—–+—–+——-+—————+————+<\/p>\n

| ‘xxx’ < ‘xxxx’ | 1<2 | 1<1 | 5.5<5 | (1+1)<(10-10) | NULL <NULL |<\/p>\n

+—————-+—–+—–+——-+—————+————+<\/p>\n

| 1 | 1 | 0 | 0 | 0 | NULL |<\/p>\n

+—————-+—–+—–+——-+—————+————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u5c0f\u4e8e\u7b49\u4e8e(<=):<\/strong>\u00a0\u4e24\u6570\u76f8\u6bd4\u8f83,\u5de6\u8fb9\u5c0f\u4e8e\u6216\u8005\u7b49\u4e8e\u53f3\u8fb9\u8fd4\u56de1,\u5426\u5219\u8fd4\u56de0<\/p>\n

MariaDB [lyshark]> select ‘xxxx’ <= ‘xxxx’ , 1<=1 , 1<=2 , 5.5<=5 , NULL<=NULL;<\/p>\n

+——————+——+——+——–+————+<\/p>\n

| ‘xxxx’ <= ‘xxxx’ | 1<=1 | 1<=2 | 5.5<=5 | NULL<=NULL |<\/p>\n

+——————+——+——+——–+————+<\/p>\n

| 1 | 1 | 1 | 0 | NULL |<\/p>\n

+——————+——+——+——–+————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u5927\u4e8e\u8fd0\u7b97\u7b26(>):<\/strong>\u00a0\u4e24\u6570\u76f8\u6bd4\u8f83,\u5de6\u8fb9\u5927\u4e8e\u53f3\u8fb9\u8fd4\u56de1,\u5426\u5219\u8fd4\u56de0<\/p>\n

MariaDB [lyshark]> select ‘xxxx’ > ‘xxx’ , 5>1 , 10>10 , NULL > NULL;<\/p>\n

+—————-+—–+——-+————-+<\/p>\n

| ‘xxxx’ > ‘xxx’ | 5>1 | 10>10 | NULL > NULL |<\/p>\n

+—————-+—–+——-+————-+<\/p>\n

| 1 | 1 | 0 | NULL |<\/p>\n

+—————-+—–+——-+————-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u5927\u4e8e\u7b49\u4e8e(>=):<\/strong>\u00a0\u4e24\u6570\u76f8\u6bd4\u8f83,\u5de6\u8fb9\u5927\u4e8e\u6216\u8005\u7b49\u4e8e\u53f3\u8fb9\u8fd4\u56de1,\u5426\u5219\u8fd4\u56de0<\/p>\n

MariaDB [lyshark]> select ‘xxxx’ >= ‘xxxx’ , 1>=1 , 1>=10 , NULL>=NULL;<\/p>\n

+——————+——+——-+————+<\/p>\n

| ‘xxxx’ >= ‘xxxx’ | 1>=1 | 1>=10 | NULL>=NULL |<\/p>\n

+——————+——+——-+————+<\/p>\n

| 1 | 1 | 0 | NULL |<\/p>\n

+——————+——+——-+————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

IS NULL\u8fd0\u7b97\u7b26(ISNULL)\u548cIS NOT NULL\u8fd0\u7b97\u7b26(ISNOTNULL):<\/strong>\u00a0is null\u5982\u679c\u4e3aNULL\u8fd4\u56de1\u5426\u5219\u8fd4\u56de0,\u800cis not null\u5219\u76f8\u53cd.<\/p>\n

MariaDB [lyshark]> select null is null , isnull(null) , isnull(1) , 1 is not null;<\/p>\n

+————–+————–+———–+—————+<\/p>\n

| null is null | isnull(null) | isnull(1) | 1 is not null |<\/p>\n

+————–+————–+———–+—————+<\/p>\n

| 1 | 1 | 0 | 1 |<\/p>\n

+————–+————–+———–+—————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

between and \u8fd0\u7b97\u7b26(expr BETWEEN min AND max):<\/strong>\u00a0\u5047\u5982expr\u5927\u4e8e\u6216\u7b49\u4e8emin\u5e76\u4e14\u5c0f\u4e8e\u6216\u7b49\u4e8emax,\u5219beetween\u8fd4\u56de1,\u5426\u5219\u8fd4\u56de0<\/p>\n

MariaDB [lyshark]> select 4 between 2 and 5 , 4 between 4 and 6 , 20 between 5 and 10;<\/p>\n

+——————-+——————-+———————+<\/p>\n

| 4 between 2 and 5 | 4 between 4 and 6 | 20 between 5 and 10 |<\/p>\n

+——————-+——————-+———————+<\/p>\n

| 1 | 1 | 0 |<\/p>\n

+——————-+——————-+———————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

letsa\u8fd0\u7b97\u7b26(least \u503c1,\u503c2…..\u503cn):<\/strong>\u00a0\u5728\u5b9a\u4e49\u7684\u6570\u503c\u5217\u8868\u4e2d\u8fd4\u56de\u6700\u5c0f\u7684\u90a3\u4e2a\u5143\u7d20\u7684\u6570\u503c<\/p>\n

MariaDB [lyshark]> select least(10,0) , least(1,2,3,4,5,6,7,8,9) , least(‘a’,’b’,’c’) , least(10,null);<\/p>\n

+————-+————————–+——————–+—————-+<\/p>\n

| least(10,0) | least(1,2,3,4,5,6,7,8,9) | least(‘a’,’b’,’c’) | least(10,null) |<\/p>\n

+————-+————————–+——————–+—————-+<\/p>\n

| 0 | 1 | a | NULL |<\/p>\n

+————-+————————–+——————–+—————-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

greatest\u8fd0\u7b97\u7b26(greatest \u503c1,\u503c2….\u503cn):<\/strong>\u00a0\u5728\u5b9a\u4e49\u7684\u6570\u503c\u5217\u8868\u4e2d\u8fd4\u56de\u6700\u5927\u7684\u90a3\u4e2a\u5143\u7d20\u7684\u6570\u503c<\/p>\n

MariaDB [lyshark]> select greatest(10,0) , greatest(1,2,3,4,5,6,7,8,9) , greatest(‘a’,’b’,’c’) , greatest(10,null);<\/p>\n

+—————-+—————————–+———————–+——————-+<\/p>\n

| greatest(10,0) | greatest(1,2,3,4,5,6,7,8,9) | greatest(‘a’,’b’,’c’) | greatest(10,null) |<\/p>\n

+—————-+—————————–+———————–+——————-+<\/p>\n

| 10 | 9 | c | NULL |<\/p>\n

+—————-+—————————–+———————–+——————-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

IN \u548cNOT IN \u8fd0\u7b97\u7b26(\u503c1 IN (\u503c1,\u503c2…..\u503cn)):<\/strong>\u00a0in\u8fd0\u7b97\u7b26\u5224\u65ad\u6307\u5b9a\u6570\u503c\u662f\u5426\u5728\u6307\u5b9a\u7684\u4e00\u4e2a\u5217\u8868\u91cc,\u6709\u5219\u8fd4\u56de1\u65e0\u5219\u8fd4\u56de0,\u800cnot in\u8fd0\u7b97\u7b26\u6070\u6070\u76f8\u53cd.<\/p>\n

MariaDB [lyshark]> select 1 in (1,2,3,4,5) , ‘lyshark’ in (‘root’,’admin’,’lyshark’);<\/p>\n

+——————+—————————————–+<\/p>\n

| 1 in (1,2,3,4,5) | ‘lyshark’ in (‘root’,’admin’,’lyshark’) |<\/p>\n

+——————+—————————————–+<\/p>\n

| 1 | 1 |<\/p>\n

+——————+—————————————–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

MariaDB [lyshark]> select 10 not in (1,2,3,4,5) , ‘lyshark’ not in (‘root’,’admin’,’lyshark’);<\/p>\n

+———————–+———————————————+<\/p>\n

| 10 not in (1,2,3,4,5) | ‘lyshark’ not in (‘root’,’admin’,’lyshark’) |<\/p>\n

+———————–+———————————————+<\/p>\n

| 1 | 0 |<\/p>\n

+———————–+———————————————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

LIKE\u5339\u914d\u8fd0\u7b97\u7b26(expr LIKE \u5339\u914d\u6761\u4ef6):<\/strong>\u00a0like\u8fd0\u7b97\u7b26\u7528\u6765\u5339\u914d\u5b57\u7b26\u4e32,\u5982\u679cexpr\u6ee1\u8db3\u6761\u4ef6\u5219\u8fd4\u56de1\u5426\u5219\u8fd4\u56de0,\u82e5expr\u6216\u5339\u914d\u6761\u4ef6\u4e2d\u4efb\u4f55\u4e00\u4e2a\u4e3aNULL\u5219\u7ed3\u679c\u4e3aNULL.<\/p>\n

LIKE\u901a\u914d\u7b26:<\/p>\n

%:\u5339\u914d\u4efb\u610f\u5b57\u7b26,\u8d2a\u5a6a\u5339\u914d
\n_:\u53ea\u5339\u914d\u4e00\u4e2a\u5b57\u7b26
\nt__:\u8868\u793a\u5339\u914d\u4ee5t\u5f00\u5934,\u957f\u5ea6\u4e3a2\u4e2a\u5b57\u7b26\u7684\u5b57\u7b26\u4e32
\n%d:\u8868\u793a\u5339\u914d\u4ee5\u5b57\u6bcdd\u7ed3\u5c3e\u7684\u5b57\u7b26\u4e32<\/p>\n

MariaDB [lyshark]> select ‘lyshark’ like ‘lyshark’ , ‘lyshark’ like ‘%k’ , ‘lyshark’ like ‘ly_____’;<\/p>\n

+————————–+———————+————————–+<\/p>\n

| ‘lyshark’ like ‘lyshark’ | ‘lyshark’ like ‘%k’ | ‘lyshark’ like ‘ly_____’ |<\/p>\n

+————————–+———————+————————–+<\/p>\n

| 1 | 1 | 1 |<\/p>\n

+————————–+———————+————————–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

regexp\u5b57\u7b26\u4e32\u5339\u914d\u8fd0\u7b97\u7b26(expr regexp \u5339\u914d\u6761\u4ef6):<\/strong>\u00a0regexp\u8fd0\u7b97\u7b26\u80fd\u591f\u66f4\u52a0\u7cbe\u786e\u7684\u5339\u914d,\u5982\u679cexpr\u6ee1\u8db3\u6761\u4ef6\u5219\u8fd4\u56de1\u5426\u5219\u8fd4\u56de0,\u82e5expr\u6216\u5339\u914d\u6761\u4ef6\u4e2d\u4efb\u4f55\u4e00\u4e2a\u4e3aNULL\u5219\u7ed3\u679c\u4e3aNULL.<\/p>\n

REGEXP\u901a\u914d\u7b26\uff1a<\/p>\n

^\uff1a\u5339\u914d\u4ee5\u8be5\u5b57\u7b26\u540e\u9762\u7684\u5b57\u7b26\u5f00\u5934\u7684\u5b57\u7b26\u4e32
\n$\uff1a\u5339\u914d\u4ee5\u8be5\u5b57\u7b26\u540e\u9762\u7684\u5b57\u7b26\u7ed3\u5c3e\u7684\u5b57\u7b26\u4e32
\n.\uff1a\u5339\u914d\u4efb\u610f\u4e00\u4e2a\u5355\u4e00\u5b57\u7b26
\n[…]\uff1a\u5339\u914d\u5728\u65b9\u62ec\u53f7\u5185\u7684\u4efb\u610f\u5b57\u7b26<\/p>\n

MariaDB [lyshark]> select ‘lyshark’ regexp ‘^l’ , ‘lyshark’ regexp ‘k$’ , ‘lyshark’ regexp ‘..shark’ , ‘lyshark’ regexp ‘[lyak]’;<\/p>\n

+———————–+———————–+—————————-+—————————+<\/p>\n

| ‘lyshark’ regexp ‘^l’ | ‘lyshark’ regexp ‘k$’ | ‘lyshark’ regexp ‘..shark’ | ‘lyshark’ regexp ‘[lyak]’ |<\/p>\n

+———————–+———————–+—————————-+—————————+<\/p>\n

| 1 | 1 | 1 | 1 |<\/p>\n

+———————–+———————–+—————————-+—————————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

 <\/p>\n

\u25c6\u903b\u8f91\u8fd0\u7b97\u7b26\u25c6<\/h3>\n\n\n\n\n\n\n\n\n
\u8fd0\u7b97\u7b26<\/strong><\/th>\n\u4f5c\u7528<\/strong><\/th>\n<\/tr>\n<\/thead>\n
NOT \u6216 !<\/td>\n\u903b\u8f91\u975e<\/td>\n<\/tr>\n
AND \u6216 &&<\/td>\n\u903b\u8f91\u4e0e<\/td>\n<\/tr>\n
OR<\/td>\n\u903b\u8f91\u6216<\/td>\n<\/tr>\n
XOR<\/td>\n\u903b\u8f91\u5f02\u6216<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

NOT\u903b\u8f91\u975e:<\/strong>\u00a0not\u6216!\u903b\u8f91\u975e\u8fd0\u7b97\u7b26,\u5f53\u64cd\u4f5c\u6570\u4e3a0\u65f6\u8fd4\u56de1,\u5f53\u64cd\u4f5c\u4e3a1\u65f6\u8fd4\u56de0,\u5f53\u64cd\u4f5c\u6570\u4e3aNULL\u65f6,\u8fd4\u56deNULL<\/p>\n

MariaDB [lyshark]> select not 1 , not(1-1) , not -10 , not NULL;<\/p>\n

+——-+———-+———+———-+<\/p>\n

| not 1 | not(1-1) | not -10 | not NULL |<\/p>\n

+——-+———-+———+———-+<\/p>\n

| 0 | 1 | 0 | NULL |<\/p>\n

+——-+———-+———+———-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

AND\u903b\u8f91\u4e0e:<\/strong>\u00a0and\u662f\u903b\u8f91\u4e0e\u8fd0\u7b97\u7b26,\u5f53\u4e24\u8fb9\u90fd\u4e3a\u771f\u662f\u7ed3\u679c\u4e3a1,\u5426\u5219\u7ed3\u679c\u4e3a0<\/p>\n

MariaDB [lyshark]> select 1 and -1 , 1 and 0 , 1 and NULL , 0 and NULL;<\/p>\n

+———-+———+————+————+<\/p>\n

| 1 and -1 | 1 and 0 | 1 and NULL | 0 and NULL |<\/p>\n

+———-+———+————+————+<\/p>\n

| 1 | 0 | NULL | 0 |<\/p>\n

+———-+———+————+————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

OR\u903b\u8f91\u6216:<\/strong>\u00a0or\u662f\u903b\u8f91\u6216\u8fd0\u7b97\u7b26,\u4e24\u8fb9\u7684\u7ed3\u679c\u5982\u679c\u6709\u4e00\u8fb9\u4e3a\u771f,\u5219\u8fd4\u56de1\u5426\u5219\u8fd4\u56de0<\/p>\n

MariaDB [lyshark]> select 1 or 1 , 1 or 0 , 1 or -1 , 1 or NULL;<\/p>\n

+——–+——–+———+———–+<\/p>\n

| 1 or 1 | 1 or 0 | 1 or -1 | 1 or NULL |<\/p>\n

+——–+——–+———+———–+<\/p>\n

| 1 | 1 | 1 | 1 |<\/p>\n

+——–+——–+———+———–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

XOR\u5f02\u6216:<\/strong>\u00a0xor\u903b\u8f91\u5f02\u6216\u8fd0\u7b97\u7b26,\u5f53\u4efb\u610f\u4e00\u4e2a\u64cd\u4f5c\u6570\u4e3anull\u65f6\u8fd4\u56denull,\u5982\u679c\u4e24\u8fb9\u90fd\u4e3a0\u5219\u8fd4\u56de1\u5426\u5219\u8fd4\u56de0<\/p>\n

MariaDB [lyshark]> select 1 xor 1 , 0 xor 0 , 1 xor 0 , 1 xor null;<\/p>\n

+———+———+———+————+<\/p>\n

| 1 xor 1 | 0 xor 0 | 1 xor 0 | 1 xor null |<\/p>\n

+———+———+———+————+<\/p>\n

| 0 | 0 | 1 | NULL |<\/p>\n

+———+———+———+————+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

 <\/p>\n

\u25c6\u79fb\u4f4d\u8fd0\u7b97\u7b26\u25c6<\/h3>\n\n\n\n\n\n\n\n\n\n\n
\u8fd0\u7b97\u7b26<\/strong><\/th>\n\u4f5c\u7528<\/strong><\/th>\n<\/tr>\n<\/thead>\n
\\<\/td>\n\u4f4d\u6216<\/td>\n<\/tr>\n
&<\/td>\n\u4f4d\u4e0e<\/td>\n<\/tr>\n
^<\/td>\n\u4f4d\u5f02\u6216<\/td>\n<\/tr>\n
<<<\/td>\n\u4f4d\u5de6\u79fb<\/td>\n<\/tr>\n
>><\/td>\n\u4f4d\u53f3\u79fb<\/td>\n<\/tr>\n
~<\/td>\n\u4f4d\u53d6\u53cd<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u4f4d\u6216(|):<\/strong>\u00a0\u4f4d\u6216\u8fd0\u7b97\u7b26,\u6309\u7167\u63d0\u4f9b\u6570\u636e\u7684\u4e8c\u8fdb\u5236\u5f62\u5f0f\u4f9d\u6b21\u6216\u8fd0\u7b97,\u6700\u540e\u8f93\u51fa\u7ed3\u679c<\/p>\n

MariaDB [lyshark]> select 10 |15 , 9|4|2 ;<\/p>\n

+——–+——-+<\/p>\n

| 10 |15 | 9|4|2 |<\/p>\n

+——–+——-+<\/p>\n

| 15 | 15 |<\/p>\n

+——–+——-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u4f4d\u4e0e(&):<\/strong>\u00a0\u4f4d\u4e0e\u8fd0\u7b97\u7b26,\u6309\u7167\u63d0\u4f9b\u6570\u636e\u7684\u4e8c\u8fdb\u5236\u5f62\u5f0f\u4f9d\u6b21\u4e0e\u8fd0\u7b97,\u6700\u540e\u8f93\u51fa\u7ed3\u679c<\/p>\n

MariaDB [lyshark]> select 10 & 15 ,9&4&2 ;<\/p>\n

+———+——-+<\/p>\n

| 10 & 15 | 9&4&2 |<\/p>\n

+———+——-+<\/p>\n

| 10 | 0 |<\/p>\n

+———+——-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u4f4d\u5f02\u6216(^):<\/strong>\u00a0\u5c06\u6307\u5b9a\u6570\u636e\u7684\u4e8c\u8fdb\u5236\u5f62\u5f0f,\u9010\u4e00\u6309\u4f4d\u6216\u8fd0\u7b97<\/p>\n

MariaDB [lyshark]> select 10 ^ 15 , 1^0 , 1^1;<\/p>\n

+———+—–+—–+<\/p>\n

| 10 ^ 15 | 1^0 | 1^1 |<\/p>\n

+———+—–+—–+<\/p>\n

| 5 | 1 | 0 |<\/p>\n

+———+—–+—–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u6309\u4f4d\u5de6\u79fb(expr<<\u9700\u8981\u5de6\u79fb\u7684\u4f4d\u6570):<\/strong>\u00a0\u5c06\u6307\u5b9a\u6570\u636eexpr,\u7684\u4e8c\u8fdb\u5236\u5f62\u5f0f,\u6309\u4f4d\u5de6\u79fb<\/p>\n

MariaDB [lyshark]> select 4 <<2;<\/p>\n

+——-+<\/p>\n

| 4 <<2 |<\/p>\n

+——-+<\/p>\n

| 16 |<\/p>\n

+——-+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u6309\u4f4d\u53f3\u79fb(expr>>\u9700\u8981\u53f3\u79fb\u7684\u4f4d\u6570):<\/strong>\u00a0\u5c06\u6307\u5b9a\u6570\u636eexpr,\u7684\u4e8c\u8fdb\u5236\u5f62\u5f0f,\u6309\u4f4d\u53f3\u79fb<\/p>\n

MariaDB [lyshark]> select 16 >>2;<\/p>\n

+——–+<\/p>\n

| 16 >>2 |<\/p>\n

+——–+<\/p>\n

| 4 |<\/p>\n

+——–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

\u6309\u4f4d\u53d6\u53cd(~):<\/strong>\u00a0\u5c06\u76f8\u5e94\u4f4d\u6570\u7684\u4e8c\u8fdb\u5236\u5f62\u5f0f,\u9010\u4f4d\u53cd\u8f6c<\/p>\n

MariaDB [lyshark]> select 5 & ~1 ;<\/p>\n

+——–+<\/p>\n

| 5 & ~1 |<\/p>\n

+——–+<\/p>\n

| 4 |<\/p>\n

+——–+<\/p>\n

1 row in set (0.00 sec)<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

\u25c6\u6570\u636e\u5e93\u76f8\u5173\u547d\u4ee4\u25c6 \u521b\u5efa\u6570\u636e\u5e93\uff1a\u00a0\u521b\u5efa\u6570\u636e\u5e93\u53ef\u4ee5\u4f7f\u7528Create database\u547d\u4ee4\uff0c\u521b\u5efa\u4e00\u4e2alyshark […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12],"tags":[],"class_list":["post-2583","post","type-post","status-publish","format-standard","hentry","category-linux"],"_links":{"self":[{"href":"https:\/\/www.xh86.me\/index.php?rest_route=\/wp\/v2\/posts\/2583","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.xh86.me\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.xh86.me\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.xh86.me\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.xh86.me\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2583"}],"version-history":[{"count":1,"href":"https:\/\/www.xh86.me\/index.php?rest_route=\/wp\/v2\/posts\/2583\/revisions"}],"predecessor-version":[{"id":2584,"href":"https:\/\/www.xh86.me\/index.php?rest_route=\/wp\/v2\/posts\/2583\/revisions\/2584"}],"wp:attachment":[{"href":"https:\/\/www.xh86.me\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2583"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.xh86.me\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2583"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.xh86.me\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2583"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}