如果重复，用空字符串替换行值 [英] Replace row value with empty string if duplicate

问题描述

如果发现重复值，是否可以用空字符串替换行值?

is it possible to replace row value with empty string if duplicate value found?

例如

SELECT ProductCode, Color FROM Product

--------------------
ProductCode | Color
--------------------
   00A0B    |  Red
   00A0B    |  Blue
   00A0C    |  Red
   00A0C    |  Black
   00A0C    |  White
--------------------

到

--------------------
ProductCode | Color
--------------------
   00A0B    |  Red
            |  Blue
   00A0C    |  Red
            |  Black
            |  White
--------------------

我使用的是 SQL Server 2012.

I'm using SQL Server 2012.

推荐答案

通常，这种类型的转换最好在应用层完成，因为结果集不是SQL-ish".也就是说，排序对于理解行很重要.

Often, this type of transformation is better done at the application layer, because the result-set is not "SQL-ish". That is, the ordering is important for understanding the rows.

但是，您可以这样做:

select (case when row_number() over (partition by ProductCode order by (select NULL)) = 1
             then ProductCode
        end) as ProductCode
       Color
from Product
order by ProductCode;

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