16.MySQL中的IN 和 NOT IN

IN()只要比较的字段或数据在给定的集合内，那么比较结果就为真，NOT IN()正好与IN()的功能相反。

1.准备

 1 CREATE DATABASE mahaiwuji;
 2 USE mahaiwuji;
 3 CREATE TABLE emp
 4 (
 5     empno INT PRIMARY KEY,
 6     ename VARCHAR(10),
 7     sal INT
 8 );
 9 INSERT INTO emp VALUES (1,'smith',2800);
10 INSERT INTO emp VALUES (2,'allen',1500);
11 INSERT INTO emp VALUES (3,'ward',3500);
12 INSERT INTO emp VALUES (4,'jones',5000);
13 INSERT INTO emp VALUES (5,'martin',1600);
14 INSERT INTO emp VALUES (6,'blake',3000);

2.IN

查找sal为1500或3000或5000的信息

1 SELECT * FROM emp WHERE sal=1500 OR sal=3000 OR sal=5000;
2 -- 等价于
3 SELECT * FROM emp WHERE sal IN (1500,3000,5000);

3.NOT IN

查找sal不是1500也不是3000也不是5000的信息

1 SELECT * FROM emp WHERE sal!=1500 AND sal!=3000 AND sal<>5000;
2 -- 等价于
3 SELECT * FROM emp WHERE sal NOT IN (1500,3000,5000);