mysql - 使用 WHERE AND GROUP BY 获取最低值的整行

Question

我想显示一个预览页面，每个图片组有一张图片，位置最低，Online=Y添加。我想在线获取该团体的全部照片(如果可能)

我有下表的图片库:

PicID(autoinc) | PicGrp(INT) | Online(Y|N) | Pos(0-10,unique within Grp) | ... | Description

1 | 1 | Y | 0
2 | 1 | Y | 1
3 | 2 | N | 1
4 | 2 | N | 3
5 | 2 | Y | 7
6 | 2 | Y | 2
7 | 2 | Y | 10

所以我想要:

1 | 1 | Y | 0 | ... | Description | Total(2)
6 | 2 | Y | 2 | ... | Description | Total(3)

单向..当然不起作用:-)

SELECT PictureID, COUNT(*) AS Total 
FROM Pictures 
WHERE MIN(Position) AND Online = 'Y' 
GROUP BY PictureGroup

Answer 1

很确定这就是您想要的:

select y.picid, y.picgrp, y.online, y.pos, count(z.picid) as total
  from pictures y
  join pictures z
    on y.picgrp = z.picgrp
   and y.online = z.online
 where y.pos = (select min(x.pos)
                  from pictures x
                 where x.picgrp = y.picgrp
                   and x.online = 'Y')
   and y.online = 'Y'
 group by y.picid, y.picgrp, y.online, y.pos