求一条sqlserver中的语句！

来源：百度知道 编辑：UC知道 时间：2024/05/03 06:39:37
有2张表，一张phototype表，字段userName，phototype，
一张photo表，字段userName,photo_id,photo_type,path,in_time
估计能看明白吧，都什么意思吧！
现在要取出每个分类下的第一张图片或者最后一张图片！
给个sql语句！
这个可以写个程序实现，可是还是想用sql语句解决。
希望不吝赐教！

取得分类下 photo_id 字段的最大或最小值即为第一或最后一张

select pt.userName,pt.phototype,ph.photo_id,ph.path,ph.in_time
from phototype pt,photo ph where pt.phototype = ph.phototype and ph.phtot_id in (select max(photo_id) from photo where pt.phototype = ph.phototype)
union
select pt.userName,pt.phototype,ph.photo_id,ph.path,ph.in_time
from phototype pt,photo ph where pt.phototype = ph.phototype and ph.phtot_id in (select min(photo_id) from photo where pt.phototype = ph.phototype)

好难回答