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)
