🔥 运算符in 🔥
运算符in允许我们在where子句中过滤某个字段的多个值
SELECT column_name FROM table_name WHERE column_name IN (value1,value2, ....)select * from employee where id=1 or id=2 or id=3;
+----+--------+------+--------+
| id | name | sex | salary |
+----+--------+------+--------+
| 1 | 张三 | 男 | 5500 |
| 2 | 李四 | 男 | 4500 |
| 3 | 张小妹 | 女 | 4500 |
+----+--------+------+--------+select * from employee where id in(1,2,3);
+----+--------+------+--------+
| id | name | sex | salary |
+----+--------+------+--------+
| 1 | 张三 | 男 | 5500 |
| 2 | 李四 | 男 | 4500 |
| 3 | 张小妹 | 女 | 4500 |
+----+--------+------+--------+
🔥 运算符like 🔥
在where子句中，有时候我们需要查询包含某个字符串的所有记录，这时候就需要用到运算符like。
SELECT column_name FROM table_name WHERE column_name LIKE '%value%'
注意 ：
1、LIKE 子句中的 % 类似于正则表达式中的 * ，匹配任意0个或多个字符
2、like子句中的 _ 匹配任意单个字符
3、like子句中如果没有%和_，就相当于运算符=的效果<br>
select * from employee where name like '张三';
+----+------+------+--------+
| id | name | sex | salary |
+----+------+------+--------+
| 1 | 张三 | 男 | 5500 |
+----+------+------+--------+
1 row in set (0.00 sec)select * from employee where name like '李%';
+----+------+------+--------+
| id | name | sex | salary |
+----+------+------+--------+
| 2 | 李四 | 男 | 4500 |
+----+------+------+--------+
1 row in set (0.00 sec)select * from employee where name like '张%';
+----+--------+------+--------+
| id | name | sex | salary |
+----+--------+------+--------+
| 1 | 张三 | 男 | 5500 |
| 3 | 张小妹 | 女 | 4500 |
+----+--------+------+--------+
2 rows in set (0.00 sec)select * from employee where name like '张_';
+----+------+------+--------+
| id | name | sex | salary |
+----+------+------+--------+
| 1 | 张三 | 男 | 5500 |
+----+------+------+--------+
1 row in set (0.00 sec)
