mysql基础语法 字段

#插入字段

mysql> desc student;

+-------+----------+------+-----+---------+-------+

| Field | Type | Null | Key | Default | Extra |

+-------+----------+------+-----+---------+-------+

| uid | int(10) | YES | | NULL | |

| names | char(20) | YES | | NULL | |

| age | int(11) | YES | | NULL | |

+-------+----------+------+-----+---------+-------+

mysql> insert into student values(1,'xiao',20);

Query OK, 1 row affected (0.04 sec)

mysql> select * from student;

+------+-------+------+

| uid | names | age |

+------+-------+------+

| 1 | xiao | 20 |

+------+-------+------+

1 row in set (0.00 sec)

插入指定字段

mysql> insert into student (uid,name) values (2,'hong');

Query OK, 1 row affected (0.00 sec)

mysql> select name,uid from student;

+------+------+

| name | uid |

+------+------+

| xiao | 1 |

| hong | 2 |

+------+------+

2 rows in set (0.00 sec)

#查看指定的数据库的表

mysql> select database();

ERROR 2006 (HY000): MySQL server has gone away

No connection. Trying to reconnect...

Connection id: 10

Current database: book

+------------+

| database() |

+------------+

| book |

+------------+

1 row in set (0.01 sec)

mysql> select * from book.student;

+------+------+------+

| uid | name | age |

+------+------+------+

| 1 | xiao | 20 |

| 2 | hong | NULL |

+------+------+------+

2 rows in set (0.00 sec)

#删除指定表

mysql> select * from student where uid=1;

+------+------+------+

| uid | name | age |

+------+------+------+

| 1 | xiao | 20 |

+------+------+------+

1 row in set (0.00 sec)

mysql> delete from student where uid=1;

Query OK, 1 row affected (0.00 sec)

#删除为空的行

mysql> delete from student where age is null;

Query OK, 1 row affected (0.00 sec)

#更新字段

mysql> select * from student;

+------+------+------+

| uid | name | age |

+------+------+------+

| 3 | hong | 30 |

| 2 | aaa | 20 |

| 1 | bbb | 30 |

+------+------+------+

3 rows in set (0.00 sec)

mysql> update student set age=26 where uid=1;

Query OK, 1 row affected (0.00 sec)

Rows matched: 1 Changed: 1 Warnings: 0

mysql> select * from student;

+------+------+------+

| uid | name | age |

+------+------+------+

| 3 | hong | 30 |

| 2 | aaa | 20 |

| 1 | bbb | 26 |

+------+------+------+

3 rows in set (0.00 sec)

#更新表指定两个字段

mysql> update student set uid=3 where age=30 and name="ccc";

Query OK, 1 row affected (0.00 sec)

Rows matched: 1 Changed: 1 Warnings: 0

mysql> select distinct * from student;

+------+------+------+

| uid | name | age |

+------+------+------+

| 5 | hong | 30 |

| 2 | aaa | 20 |

| 1 | bbb | 26 |

| 4 | ccc | 20 |

| 3 | ccc | 30 |

+------+------+------+

5 rows in set (0.00 sec)