有如下表结构：
picid uid field1 field2 …
1 9527
2 9528
3 9528
4 9527
…
也就是每个用户对应N张图片，现在需要找出指定的每个用户的前4张图片，求这个sql语句，多谢！
picid uid field1 field2 …
1 9527
2 9528
3 9528
4 9527
…
也就是每个用户对应N张图片，现在需要找出指定的每个用户的前4张图片，求这个sql语句，多谢！
解决方案
5
select * from table where uid = “” order by picid limit 4
20
select *
from tb A
where 4>=(select count(*) from tb B where A.uid=B.uid and A.uid<B.uid)
from tb A
where 4>=(select count(*) from tb B where A.uid=B.uid and A.uid<B.uid)
20
SELECT * FROM ( SELECT *, (SELECT COUNT(*) FROM TB T2 WHERE T1.UID = T2.UID AND T1.PICID <= T2.PICID) RN FROM TB T1 )T WHERE RN <= 4
20
select * from (
select *,row_number over(partition by uid order by picid asc) as idd from table where uid in (9527,9528…)
where idd <=4;
select *,row_number over(partition by uid order by picid asc) as idd from table where uid in (9527,9528…)
where idd <=4;
20
select *
from tb A
where 4>=(select count(*) from tb B where A.uid=B.uid and A.picid<B.picid)
from tb A
where 4>=(select count(*) from tb B where A.uid=B.uid and A.picid<B.picid)
15
