可以与窗口函数交叉连接工作，如 - row_number() 函数答案

【问题标题】：Can cross join work with window function like - row_number() function可以与窗口函数交叉连接工作，如 - row_number() 函数
【发布时间】：2015-03-13 06:34:26
【问题描述】：

不能在 where 子句中使用窗口函数。在下面的查询中，rn 列只能在外部查询中的 where 子句中使用，例如 -

select * from (
select *, row_number() over (partition by col1 order by col1) as rn 
from tab1) as abc
where rn = 1

我们可以使用带有交叉连接的 rn 列吗？比如 -

select *, row_number() over (partition by col1 order by col1) as rn 
from tab1 as a
cross join(select rn from a)

Just curious to know as i am trying to learn SQL server

【问题讨论】：

标签： sql-server

【解决方案1】：

你不能这样做。您要么必须在子查询中重复 ROW_NUMBER()：

SELECT *, ROW_NUMBER() OVER (PARTITION BY col1 ORDER BY col1) AS rn 
FROM tab1 AS a
CROSS JOIN (SELECT ROW_NUMBER() OVER (PARTITION BY col1 ORDER BY col1) AS rn FROM tab1) t

或者，或者，使用通用表表达式：

;WITH a AS (
   SELECT *, ROW_NUMBER() OVER (PARTITION BY col1 ORDER BY col1) AS rn 
   FROM tab1
)
SELECT *
FROM a
CROSS JOIN (SELECT rn FROM a) t

【讨论】：