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:
(select GROUP_CONCAT(j.work_name) as work_name from recruitment_jobs j where FIND_IN_SET(j.recruitment_id,d.id)) as work_name,
(select sum(j.user_num) from recruitment_jobs j where FIND_IN_SET(j.recruitment_id,d.id)) as user_num
FROM
recruitment_demand d
结果图: