mysql 基础
目录
DML操作
INSERT语句
[root@lnh ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 26
Server version: 5.7.38 MySQL Community Server (GPL)
Copyright (c) 2000, 2022, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> set global validate_password_policy=0;
Query OK, 0 rows affected (0.00 sec)
//设置密码的等级
mysql> set global validate_password_length=1;
Query OK, 0 rows affected (0.00 sec)
//设置密码的长度
mysql> insert into tsb(id,name,age) value(1,'zhangsan',20);
Query OK, 1 row affected (0.00 sec) //一次插入一条记录
mysql> insert into tsb(id,name,age) values(1,'lisi',20),(2,'wangwu',21),(3,'laoliu',21),(2,'zhaoqi',null);
Query OK, 4 rows affected (0.00 sec) //多次插入一条记录
Records: 4 Duplicates: 0 Warnings: 0
mysql> select * from tsb;
+----+----------+------+
| id | name | age |
+----+----------+------+
| 1 | zhangsan | 20 |
| 1 | lisi | 20 |
| 2 | wangwu | 21 |
| 3 | laoliu | 21 |
| 2 | zhaoqi | NULL |
+----+----------+------+
5 rows in set (0.00 sec)
//查询读取数据
SELECT语句
mysql> select * from tsb;
+----+----------+------+
| id | name | age |
+----+----------+------+
| 1 | zhangsan | 20 |
| 1 | lisi | 20 |
| 2 | wangwu | 21 |
| 3 | laoliu | 21 |
| 2 | zhaoqi | NULL |
+----+----------+------+
5 rows in set (0.00 sec)
//查询tsb的数据
mysql> select name from tsb;
+----------+
| name |
+----------+
| zhangsan |
| lisi |
| wangwu |
| laoliu |
| zhaoqi |
+----------+
5 rows in set (0.01 sec)
//查看tsb的名字
mysql> select * from tsb order by age;
+----+----------+------+
| id | name | age |
+----+----------+------+
| 2 | zhaoqi | NULL |
| 1 | zhangsan | 20 |
| 1 | lisi | 20 |
| 2 | wangwu | 21 |
| 3 | laoliu | 21 |
+----+----------+------+
5 rows in set (0.00 sec)
//查询tsb以年龄进行升序排序
mysql> select * from tsb order by age desc;
+----+----------+------+
| id | name | age |
+----+----------+------+
| 2 | wangwu | 21 |
| 3 | laoliu | 21 |
| 1 | zhangsan | 20 |
| 1 | lisi | 20 |
| 2 | zhaoqi | NULL |
+----+----------+------+
5 rows in set (0.00 sec)
//查询tsb以年龄进行降序排序
mysql> select * from tsb order by age limit 2;
+----+----------+------+
| id | name | age |
+----+----------+------+
| 2 | zhaoqi | NULL |
| 1 | zhangsan | 20 |
+----+----------+------+
2 rows in set (0.00 sec)
//查询tsb以年龄进行升序排序并只取前2个结果
mysql> select * from tsb order by age limit 1,2;
+----+----------+------+
| id | name | age |
+----+----------+------+
| 1 | zhangsan | 20 |
| 1 | lisi | 20 |
+----+----------+------+
2 rows in set (0.00 sec)
//查询tsb以年龄进行升序排序并且略过第1个结果取后面的2个结果
mysql> select * from tsb where age=20;
+----+----------+------+
| id | name | age |
+----+----------+------+
| 1 | zhangsan | 20 |
| 1 | lisi | 20 |
+----+----------+------+
2 rows in set (0.00 sec)
//以这个年龄段的进行查询
mysql> select * from tsb where age=20 and name='zhangsan';
+----+----------+------+
| id | name | age |
+----+----------+------+
| 1 | zhangsan | 20 |
+----+----------+------+
1 row in set (0.00 sec)
//以这个年龄段和名字进行查询
mysql> select * from tsb where age=20 or name='zhangsan';
+----+----------+------+
| id | name | age |
+----+----------+------+
| 1 | zhangsan | 20 |
| 1 | lisi | 20 |
+