where in 数据查询的用法

---查询被当做黑名单人物次数排名前20的用户
select Top 20 db_owner.Relation.QQID,COUNT(db_owner.Relation.RelationStatus) AS 黑名单次数 from  db_owner.Relation
group by db_owner.Relation.QQID,db_owner.Relation.RelationStatus
order by db_owner.Relation.RelationStatus  desc
--获取好友超过20个的用户QQ号码结果集 ,然后等级加一级
update db_owner.QQuser set level=level+1
where QQID in(
select QQID from db_owner.relation
where relation.relationstatus=0
group by db_owner.relation.QQID
having count(relation.QQid)>=20
)
--删除黑名单中的用户
delete from db_owner.Relation where db_owner.Relation.RelationStatus=1
--删除违规用户
--删除超过1000天没有登录过的QQ
--删除Relation表中的数据，利用IN关键字模糊匹配QQID集
delete from db_owner.Relation
where QQID in (
select QQID from db_owner.relation
where relation.relationstatus=0 and relation.relationstatus=1
group by db_owner.relation.QQID
)