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sql关于相同父ID最多取3记录

程序员文章站 2022-04-30 14:52:35
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表 imginfo
id fid miaoshu
1 3 aaaaaaa
2 3 sssssss
3 3 fffff
4 4 uuuuuuuu
5 5 gfgfgfgfgf
6 5 ddfdfdfd
7 9 fdffdfd
8 9 dfdfdfd
9 9 dfdfdf
10 9 popopop
11 3 tgtrtyrtyry
12 5 fdsjfdfdl

SELECT * FROM `imginfo` WHERE fid in(3,5,9) ORDER BY `id` DESC
上面这条语句fid 3,5,9全部内容都获取了。

现在我只想每条相同fid最多获取3条,排序不变,sql语句怎么写?
请大家指教请高人指教。不胜感激!


回复讨论(解决方案)

你SQL取出来在php那端每个值取3个不就结了?

拍完序之后仅获取前三条的话可以用limit0,3;


select a.* from imginfo a where 3 > (select count(*) from imginfo where fid = a.fid and id > a.id and fid in(3,5,9)) and fid in(3,5,9) order by a.fid,a.id

SQL语句如下:
select a.* from imginfo a where 3 > (select count(*) from imginfo where fid = a.fid and id > a.id and fid in(3,5,9)) and fid in(3,5,9) order by a.fid,a.id

如果只是按ID降序,排序改下就好
select a.* from imginfo a where 3 > (select count(*) from imginfo where fid = a.fid and id > a.id and fid in(3,5,9)) and fid in(3,5,9) order by a.id desc

可以这样的哦,学习了。

学习了!谢谢版主。


select a.* from imginfo a where 3 > (select count(*) from imginfo where fid = a.fid and id > a.id and fid in(3,5,9)) and fid in(3,5,9) order by a.fid,a.id

版主 想问下 我想按照条数的多少来排序该怎么做呢?比如fid 为3的有5条 为9的有10条 为5的有3条 排序就为 9 3 5 请问怎么实现了 谢谢了