和果果的聊天记录
//作业
update player set flag=flag(now > kaihua )
from player innerjoin keng on player.id=keng.playerid
//
select distinct playerId from keng
where time > kuhua
inner join player
update player
set kaiuia=case
from
select kaihuale=case...
explain
kddkkasl
select * from player
(
select *
keng
where time>kdakf
grup by
)
inner join id=id kaihua
//这个不错
(pid)
select player.*
from (
select distinct playerId from keng
inner join
(
select friendId from friend where playerId=(pid)
) on id=id
where time>now
) as t
left join player on id=id
//
select case when exists (select 1 from keng ) from player