腊月的季节

SQL语句笔记

sql语句实用

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> select 'true' as isfromme from ceshi;
> select name,case when when id=1 then 'true' else 'false' end isfrome from ceshi;
> select sid,rid,message,isread from userchat where
sid=7 and (rid in (select uid2 from friend where uid1=7) or rid in (select uid1 from friend where uid2=7)) or (sid in (select uid2 from friend where uid1=7) or sid in (select uid1 from friend where uid2=7)) and rid=7;
> select case when uid1=7 then uid2 else uid1 end uid from friend where uid1=7 or uid2=7;
> select uid,uname,uimage from user where uid in (select case when uid1=7 then uid2 else uid1 end uid from friend where uid1=7 or uid2=7)
> select count(isread=0),message lastmessage,date_format(time,'%Y-%c-%d %h:%i:%s') time from userchat where rid=7 and sid=9 or rid=9 and sid=7 GROUP BY isread,message,time ORDER BY time desc LIMIT 1;
> select count(isread=0 or null) from userchat where rid=?
> select fid,uname,uimage,signature from follow a inner join user b on a.fid=b.uid where a.uid=7;

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