MySQL中find_in_set()函数用法示例详解

SELECT FIND_IN_SET('b', 'a,b,c,d');
// 结果：2
// 因为 b 在strlist集合中2的位置, a是位置1

select FIND_IN_SET('1', '1');
// 结果：1 
// 这时候的strlist集合有点特殊，只有一个字符串

select FIND_IN_SET('2', '1,2'); 
// 结果：2

select FIND_IN_SET('6', '1'); 
// 结果：0 strlist中不存在str，所以返回0。

CREATE TABLE `test` (
  `ID` int(11) NOT NULL,
  `LIST` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `test` VALUES ('1', 'AA,BB,CC');
INSERT INTO `test` VALUES ('2', 'AA,BB');
INSERT INTO `test` VALUES ('3', 'AA');

-- IN查询字段条件
SELECT id,list,'字段条件' AS 'IN字段' from TEST WHERE list in ('AA');

-- IN查询常量条件-条件为真
SELECT id,list,'条件为真' AS 'IN常量条件为真' from TEST WHERE 'AA' in ('AA','BB');

-- IN查询常量条件-条件为假
SELECT id,list,'条件为假' AS 'IN常量条件为假'  from TEST WHERE 'AA' in ('BB','CC');

-- FIND_IN_SET字段条件
SELECT id,list,'字段条件' AS 'FIND_IN_SET字段' from TEST WHERE FIND_IN_SET('AA', list);

-- FIND_IN_SET常量条件为真
SELECT id,list,'条件为真' AS 'FIND_IN_SET常量条件为真' from TEST WHERE FIND_IN_SET('AA', 'AA,BB,CC');

-- FIND_IN_SET常量条件为假
SELECT id,list,'条件为假' AS 'FIND_IN_SET常量条件为假' from TEST WHERE FIND_IN_SET('AA', 'BB,CC');

SELECT id,list FROM TEST WHERE FIND_IN_SET(list,'AA,BB')

select * from article where FIND_IN_SET('4',type)

SELECT dept_id FROM sys_dept WHERE dept_id = 100 or FIND_IN_SET( 100 , ancestors )