mysql 查询的问题

Question

client表
有一个字段visit_id,对应的是visit表的id,多个以逗号分开

visit表

现在我想查询client表中关联visit表其中有activity_id=42和turn_up=1的记录

Answer 1

select a*,b* from client a left join visit b on a.visit_id = b.id where b.activity_id=42 and b.turn_up=1

Answer 2

select ct.* from client ct, (select vt.id from visit vt where vt.activity_id = 42 and vt.turn_up=1) as vtid where ct.visit_id like CONCAT("%",CONCAT(vtid.id,"%"))