SQL服务器 - 从一组

Question

获取第一条记录我有这样

我想下面的代码，以获得第一条记录从“的AdID”组

;with cte as 
(
    select 
    ADID, 
    PhotoName, 
    PhotoPath, 
    rank() over(partition by AdID order by PhotoName) as rn 
    from AdPhoto 
) 
select ADID, 
    PhotoName, 
    PhotoPath 
from cte 
where rn = 1 

一个表，但事实证明出这样的

AD1001 temptemp_1.jpeg ~/UserUploads/temptemp/ 
AD1002 temptemp_10.jpg ~/UserUploads/temptemp/ 

输出我想这样一个

输出

AD1001 temptemp_1.jpeg ~/UserUploads/temptemp/ 
AD1002 temptemp_5.jpg ~/UserUploads/temptemp/ 

请帮

Answer 1

请尝试order by ID而不是order by PhotoName：

;with cte as 
(
    select 
    ADID, 
    PhotoName, 
    PhotoPath, 
    rank() over(partition by AdID order by ID) as rn 
    from AdPhoto 
) 
select ADID, 
    PhotoName, 
    PhotoPath 
from cte 
where rn = 1 

Answer 2

这将帮助这个特殊的一组数据：

;with cte as 
(
    select 
    ADID, 
    PhotoName, 
    PhotoPath, 
    rank() over(partition by AdID order by len(PhotoName) asc, PhotoName) as rn 
    from AdPhoto 
) 
select ADID, 
    PhotoName, 
    PhotoPath 
from cte 
where rn = 1 

但我建议要么改变photoname的命名方案，或找到其他的排序算法。