数据库 基础篇4（mysql语法---表）

Posted 2020-08-14

5 表管理

选择数据库

 

  5.1 查看所有表

mysql> show tables; +-----------------+ | Tables_in_day15 | +-----------------+ | student         | +-----------------+ 1 row in set (0.00 sec)

 

  5.2 创建表

mysql> create table student(     -> sid int,     -> sname varchar(20),     -> sage int     -> ); Query OK, 0 rows affected (0.01 sec)

 

  5.3 查看表结构

mysql> desc student; +-------+-------------+------+-----+---------+-------+ | Field | Type        | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | sid   | int(11)     | YES  |     | NULL    |       | | sname | varchar(20) | YES  |     | NULL    |       | | sage  | int(11)     | YES  |     | NULL    |       | +-------+-------------+------+-----+---------+-------+ 3 rows in set (0.01 sec)

 

5.4 删除表

 

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

 

5.5 修改表

1）添加字段

 

mysql> alter table student add column sgender varchar(2); Query OK, 0 rows affected (0.03 sec) Records: 0  Duplicates: 0  Warnings: 0

 

   2）删除字段

 

mysql> alter table student drop column sgender; Query OK, 0 rows affected (0.03 sec) Records: 0  Duplicates: 0  Warnings: 0

 

3）修改字段类型

 

mysql> alter table student modify column remark varchar(100); Query OK, 0 rows affected (0.07 sec) Records: 0  Duplicates: 0  Warnings: 0

 

4）修改字段名称

 

mysql> alter table student change column sgender gender varchar(2); Query OK, 0 rows affected (0.03 sec) Records: 0  Duplicates: 0  Warnings: 0

 

5）修改表名称

 

mysql> alter table student rename to teacher; Query OK, 0 rows affected (0.01 sec)