选择列相关的所有行

Question

我有一个Url表

UrlId   Followedby
1            NULL
2            1
3            2

我想写一个sp，它将urlid作为参数并返回所有行。 GetAllUrls 3 它会返回上面的行。

没有光标可以上面吗？

Answer 1

查看Recursive Queries Using Common Table Expressions。

Answer 2

使用递归CTE，它看起来像这样

declare @UrlId int = 3

;with C as 
(
  select U.UrlId,
         U.Followedby
  from Url as U
  where U.UrlId = @UrlId
  union all
  select U.UrlId,
         U.Followedby
  from Url as U
    inner join C
      on U.UrlId = C.Followedby
)
select UrlId,
       Followedby 
from C

http://data.stackexchange.com/stackoverflow/q/119027/