Over () Partition By () Query - SQL Server Forums

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Over () Partition By () Query

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Topic

funk.phenomena
Posting Yak Master

121 Posts

Posted - 2012-08-10 : 13:12:00

Hi All - I have the following Table:

I am trying to identify which of these are duplicates, by having the output as follows:


Serial_Num | DUPLICATE

123456 Y
123456 Y
123456 Y
123457 N
123458 N
123459 N

I've used the over by/partition by function, but I need to replace it with a Y/N as described above.


    SELECT * FROM 
    
    (SELECT Serial_Num, ROW_NUMBER() OVER (PARTITION BY Serial_Num ORDER BY Serial_Num) AS Rn FROM MyTable) T1

Any ideas? Thanks!

robvolk
Most Valuable Yak

15732 Posts

Posted - 2012-08-10 : 13:45:52

SELECT Serial_Num, CASE WHEN COUNT(*) OVER (PARTITION BY Serial_Num)>1 THEN 'Y' ELSE 'N' END Duplicate FROM MyTable

funk.phenomena
Posting Yak Master

121 Posts

Posted - 2012-08-10 : 15:57:34

Thanks! Works great!

madhivanan
Premature Yak Congratulator

22864 Posts

Posted - 2012-08-16 : 08:54:52

Also

SELECT Serial_Num,case when count(*)>1 then 'Y' else 'N' end as duplicate from table
group by Serial_Num

Madhivanan

Failing to plan is Planning to fail

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