SQL Server函数ROW_NUMBER（）OVER（PARTITION BY不计算

Question

我对ROW_NUMBER() OVER(PARTITION BY ....)函数有问题。

这是我使用的原始表格：

PRODUCT    VERSION   Colour
------------------------------
Apple        7.1      Black
Apple        7.1      Blue
Apple        7.1      Red
Apple        2.0      NULL
Beer         12.8     Blue 
Beer         12.8     NULL
Beer         12.8     NULL
Bread        14.87    Blue  
Bread        14.87    NULL
Bread        14.87    Orange  
Notes        100      Red 
Notes        100      NULL
Car          NULL     Green
Car          NULL     Blue
Car          NULL     Red
Car          NULL     Red     

我针对此表运行此脚本：

SELECT 
    [product], [version], [colour],
    ROW_NUMBER() OVER (PARTITION BY [product], [Version] ORDER BY [product] DESC) AS COUNT2  
FROM 
    TABLE1

然后我得到这样的输出：

PRODUCT    VERSION   Colour  COUNT2
-----------------------------------
Apple        7.1      Black   1
Apple        7.1      Blue    2
Apple        7.1      Red     3
Apple        2.0      NULL    4
Beer         12.8     Blue    1
Beer         12.8     NULL    2
Beer         12.8     NULL    3
Bread        14.87    Blue    1
Bread        14.87    NULL    2
Bread        14.87    Orange  3
Notes        100      Red     1   
Notes        100      NULL    2
Car          NULL     Green   1
Car          NULL     Blue    2
Car          NULL     Red     3
Car          NULL     Red     4

然后我选择具有最大值的行

SELECT 
    [Product], [Version], MAX(COUNT2)
FROM 
    [dbo].[TABLE1] 
GROUP BY 
    Product, Version

但是我有问题。 运行函数ROW_NUMBER() OVER(PARTITION BY ...)时我无法获得相同的数字，仅取决于1列

如果我计算回来的方法，我将无法计算回来并获得正确的结果。

PRODUCT   VERSION    COUNT2
----------------------------
Apple       7.1       6
Apple       2.0       7
Beer        12.8      5
Bread       14.87     1 
Notes       100       6
Car         NULL      8

如果我最后运行没有版本的脚本，那么在进行反向计算时会得到不同的数字

SELECT 
    [product], [version], [colour],
    ROW_NUMBER() OVER(PARTITION BY [product], ORDER BY [product] DESC) AS COUNT2  
FROM 
    TABLE1

SELECT 
    [Product], MAX(COUNT2)
FROM 
    [dbo].[TABLE1] 
GROUP BY 
    Product

结果与我预期的不同：

PRODUCT    COUNT
----------------
Apple        4
Beer         3
Bread        3
Notes        2
Car          4

我期望这样的结果：

PRODUCT   VERSION    COUNT2
----------------------------
Apple       7.1       3
Apple       2.0       1
Beer        12.8      3
Bread       14.87     3 
Notes       100       2
Car         NULL      4

感谢您的帮助，我设置了函数ROW_NUMBER() OVER(PARTITION BY....)

原始表有10000多行。

Answer 1

试试这个：

SELECT 
    [product], [version], COUNT(*)  
FROM 
    TABLE1
GROUP BY [product], [version]

告诉我它是否能满足您的需求

PS：您肯定有复制/粘贴问题：此代码可以正常工作：

Answer 2

只需添加count（）以及查询分区

Select  PRODUCT,[VERSION], COUNT2 from  (
Select DISTINCT 
        PRODUCT, 
        VERSION,
        Count(COUNT2)OVER(PARTITION BY version )COUNT2 from (
SELECT 
    [product], 
    [version], 
    [colour],
    ROW_NUMBER() OVER (PARTITION BY [product], [Version] ORDER BY [product] DESC) AS COUNT2  
FROM 
    @Table1 )T
    GROup BY  PRODUCT, VERSION,COUNT2 )TT


    ORDER BY CASE WHEN VERSION IS NOT NULL then 0 else 1 END