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

Question

I have problem with the ROW_NUMBER() OVER(PARTITION BY ....) function.

This is my original table which I work with:

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     

I run this script against this table:

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

Then I get an output like this:

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

Then I select rows with maximal values

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

But here I have problem. I can not get same numbers when I run function ROW_NUMBER() OVER(PARTITION BY ...) depend only on 1 column

I can not calculate back and get correct result if I calculate back way.

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

If I run script without version on the end I am getting different numbers when I do calculation back way

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

Result is different than what I am expecting:

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

I expected a result like this :

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

Thanks for help me to setup function ROW_NUMBER() OVER(PARTITION BY....)

Original table has over 10000 rows..

Answer 1

Try this one:

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

and tell me if it gives you what you want

PS You definitely have a problem with copy/paste: this code works fine:

Answer 2

Just add count()along with partition for your query

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