MySql 查询出对应子表的某个字段，并且关联起来

1、用到MySQL的 FIND_IN_SET() 函数。

2、主表：recruitment_demand，子表：recruitment_jobs

需求：需要查询出主表以及关联的子表中的work_name、和user_num字段，work_name拼接起来用逗号隔开，以及统计user_num的总和。

查询语句：

结果图：

create table a (name varchar(20) not null,sex varchar(10))

create table b (name varchar(20) not null,sex varchar(10))

2、插入值

insert into a values('john','male')insert into b values('john','male')

insert into a values('kate','female')insert into b values('kate','female')

3、查询方法1

mysql>select name,sex from a where name in (select name from b where name='john')

+------+------+

| name | sex |

+------+------+

| john | male |

+------+------+

1 row in set (0.00 sec)

4、查询方法2

mysql>select a.name,a.sex from a,b where a.name=b.name and b.name='john'

+------+------+

| name | sex |

+------+------+

| john | male |

+------+------+

1 row in set (0.00 sec)