常用sql

1、将列拼接成字符串

　　

SELECT top 10 CAST(ID as varchar)+',' FROM T_AppPush FOR XML PATH('')

2、更新表数据（根据令一张关联表）

update T_Wenwen set IsReply=
case when b.UserType=1 then 0
    when b.UserType=2 then 1
end
from T_Wenwen a inner join (select * from T_WenwenReply where ID in ( select MAX(ID) from T_WenwenReply where DeleteStatus=0 group by WenwenID)) b on a.Id=b.WenwenID