如何在此查询中使用ROW_NUMBER？

Question

我是一个新的SQL Server，并具有以下查询：

SELECT distinct top 10 ExecuteDate 
FROM [ClubEatc].[dbo].[GetOnlineBills] 
ORDER BY ExecuteDate DESC 

我应该用在查询Row_Number，我怎么可以编写查询？

谢谢大家。

Answer 1

如果你想有一个编号为每一行和每一ExecuteDate应该是不同的：

WITH CTE AS 
(
    SELECT DISTINCT ExecuteDate FROM [ClubEatc].[dbo].[GetOnlineBills] 
) 
SELECT TOP 10 ExecuteDate, RN = ROW_NUMBER() OVER (ORDER BY ExecuteDate DESC) 
FROM CTE 
ORDER BY ExecuteDate DESC 

或GROUP BY：

SELECT TOP 10 ExecuteDate, RN = ROW_NUMBER() OVER (ORDER BY ExecuteDate DESC) 
FROM [ClubEatc].[dbo].[GetOnlineBills] 
GROUP BY ExecuteDate 
ORDER BY ExecuteDate DESC 

---

也许你想看到整个记录，但只有每个ExecuteDate-Group的第一个。然后，这个查询将工作：

WITH CTE AS 
(
    SELECT ExecuteDate, 
      RN_DESC = ROW_NUMBER() OVER (PARTITION BY ExecuteDate 
             ORDER BY ExecuteDate DESC) 
    FROM [ClubEatc].[dbo].[GetOnlineBills] 
) 
SELECT TOP 10 ExecuteDate 
FROM CTE 
WHERE RN_DESC = 1 
ORDER BY ExecuteDate DESC 

而是仅列ExecuteDate你可以列出所有。但是ExecuteDate是要分组的列，并且您没有告诉我们要将哪个列用于每个组的排序，因此您希望查看每个ExecuteDate组的哪一行。所以目前这个查询返回每个组的任意一行。将PARTITION BY ExecuteDate ORDER BY ExecuteDate DESC更改为f.e. PARTITION BY ExecuteDate ORDER BY AnotherDateOrIdColumn DESC以获得更有意义的结果。

Answer 2

你的意思是这样的：

SELECT distinct top 10 ROW_NUMBER() OVER(ORDER BY ExecuteDate DESC), ExecuteDate 
FROM [ClubEatc].[dbo].[GetOnlineBills] 
ORDER BY ExecuteDate DESC 

Answer 3

您可以使用：

SELECT TOP 10 ExecuteDate 
FROM (
    SELECT ExecuteDate, 
      ROW_NUMBER() over (PARTITION BY ExecuteDate ORDER BY ExecuteDate DESC) as RN 
    FROM [GetOnlineBills] 
) as t 
WHERE RN = 1 
ORDER BY ExecuteDate DESC 

或者：

SELECT TOP 10 ExecuteDate 
FROM (
    SELECT TOP 1 WITH TIES ExecuteDate 
    FROM [GetOnlineBills] 
    ORDER BY ROW_NUMBER() over (PARTITION BY ExecuteDate ORDER BY ExecuteDate DESC) 
) as t 
ORDER BY ExecuteDate DESC