MySQL增删查改基本命令

1、建立数据库

语法：create database 数据库名；

实例：

mysql> create database shujuku;
Query OK, 1 row affected (0.10 sec)

2、进入数据库

语法：use 数据库名；

实例：

mysql> use shujuku;
Database changed

3、新建表

语法：create table 表名(字段，...);

实例：

mysql> CREATE TABLE class1 (
    -> id SMALLINT UNSIGNED AUTO_INCREMENT ,
    -> name VARCHAR(30) NOT NULL UNIQUE KEY ,
    ->  school VARCHAR(30) DEFAULT 'jilin_university',
    ->  PRIMARY KEY(id)
    -> );
Query OK, 0 rows affected (0.18 sec)

4、查看表结构

语法： desc 表名;

实例：

mysql> desc class1;
+--------+----------------------+------+-----+------------------+----------------+
| Field  | Type                 | Null | Key | Default          | Extra                   |
+--------+----------------------+------+-----+------------------+----------------+
| id     | smallint(5) unsigned | NO   | PRI | NULL             | auto_increment |
| name   | varchar(30)          | NO   | UNI | NULL             |                            |
| school | varchar(30)          | YES  |     | jilin_university |                             |
+--------+----------------------+------+-----+------------------+----------------+
3 rows in set (0.05 sec)

5、插入

语法：insert into 表名 set 字段名=‘字段值’,...;

实例：

mysql> insert into class1 set name='baiyang',school='nanhugaozhong';
Query OK, 1 row affected (0.00 sec)


mysql> insert into class1 set name='yueyue';
Query OK, 1 row affected (0.00 sec)

6、修改

语法：update 表名 set 字段=‘修改值’ where 字段=‘原值’,...;

实例：

mysql> update class1 set name='lala' where name='yueyue';
Query OK, 1 row affected (0.04 sec)
Rows matched: 1  Changed: 1  Warnings: 0


mysql> select * from class1;
+----+---------+------------------+
| id | name    | school           |
+----+---------+------------------+
|  1 | baiyang | nanhugaozhong    |
|  2 | lala    | jilin_university |
+----+---------+------------------+
2 rows in set (0.00 sec)

7、删除

语法：delete from 表名 where 条件;

实例：

mysql> delete from class1 where school='jilin_university';
Query OK, 1 row affected (0.00 sec)


mysql> select * from class1;
+----+---------+---------------+
| id | name    | school        |
+----+---------+---------------+
|  1 | baiyang | nanhugaozhong |
+----+---------+---------------+
1 row in set (0.00 sec)

语法：drop table 表名;

实例：

mysql> drop table class1;
Query OK, 0 rows affected (0.01 sec)

语法：drop database 数据库名;

实例：

mysql> drop database shujuku;
Query OK, 0 rows affected (0.36 sec)

8、查询

语法：select * from 表名;     简单查询

实例：

mysql> select * from class1;
+----+---------+------------------+
| id | name    | school             |
+----+---------+------------------+
|  1 | baiyang | nanhugaozhong    |
|  2 | yueyue  | jilin_university        |
+----+---------+------------------+
2 rows in set (0.00 sec)

语法：select * from 表名 where 条件;     条件查询

实例：

mysql> select * from class1 where id>1;
+----+--------+------------------+
| id | name   | school           |
+----+--------+------------------+
|  2 | yueyue | jilin_university |
+----+--------+------------------+
1 row in set (0.06 sec)

语法：select * from 表名 group by 字段 desc;    分组查询

实例：

mysql> select * from class1 group by school desc;
+----+---------+------------------+
| id | name    | school           |
+----+---------+------------------+
|  1 | baiyang | nanhugaozhong    |
|  2 | yueyue  | jilin_university |
+----+---------+------------------+
2 rows in set (0.06 sec)

语法：select * from 表名 order by 字段 desc;   排序查询，升序asc,降序desc

实例：

mysql> select * from class1 order by id desc;
+----+---------+------------------+
| id | name    | school           |
+----+---------+------------------+
|  2 | yueyue  | jilin_university |
|  1 | baiyang | nanhugaozhong    |
+----+---------+------------------+
2 rows in set (0.00 sec)