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Find and Mark Duplicate Records in SQL table

Hello, I am working in SQL Server 2005. I am trying to mark duplicate records. Let's say I have these records in a table:

John Bobbit
John Wayne
Mark McSteele
John Bobbit
Rosario Jake
Mark McSteele
Maria Mandrake
John Willis
Mark McSteele
John Bobbit
John Wayne

First I would need to find which ones contain duplicates. Then, I'd need to mark them with a number sequence based on the number of duplicates. For example, in this list
      John Bobbit,
      Mark McSteele, and
      John Wayne have duplicates.
John Bobbit has 3, Mark McSteele also has 3, but John Wayne has 2.

I want to update a field in this table so they get marked like this:

1 John Bobbit
1 John Wayne
1 Mark McSteele
2 John Bobbit
1 Rosario Jake
2 Mark McSteele
1 Maria Mandrake
1 John Willis
3 Mark McSteele
3 John Bobbit
2 John Wayne

As you can see there's a 1, 2, and 3 mark for both John Bobbit and Mark McSteele; 1 and 2 for John Wayne; but the rest are marked as 1 because they don't have duplicates.

Any ideas?

Thanks!

TheUndecider

ASKER

I'd also would like to point out all of these records have an unique ID that could be used to update the mark field.

Sharath S

try this.

select row_number() over (partition by your_column order by your_column) as seq_num,
       your_column
  from your_table

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Sharath S

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TheUndecider

ASKER

Thanks for your answer. This is exactly what I was looking for.