Delete Duplicates

Hi I have a table and  need to identify duplicates by creating an unique key  by concatenating col1+Col2+col3 and then keep last occurring duplicate for each group of duplicates.

How can we achieve this?
SrivAsked:
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Jim HornMicrosoft SQL Server Data DudeCommented:
Thre's really not enough details here to give you a rock-solid solution, but the article SQL Server Delete Duplicate Rows should give you a wompload of help.
Máté FarkasDatabase Developer and AdministratorCommented:
You don't need to concatenate keys.
You can do it this way:
WITH CTE AS (
        SELECT *, ROW_NUMBER() OVER(PARTITION BY Col1, Col2, Col3) Rn
        FROM dbo.YourTable
)
DELETE FROM CTE
WHERE Rn > 1

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SrivAuthor Commented:
Mate your Answer keeps the first unique record and deletes the rest. however I need to keep the last unique record and delete the rest
Máté FarkasDatabase Developer and AdministratorCommented:
Ok, what is the definition of first record and last in your table?
SrivAuthor Commented:
Mate the above solution that you provided find duplicates and keeps first occurring (Ranked 1) duplicate and deletes other duplicates but my requirement is to keep the last ranked duplicate. We also have ID column which is identity column. We need to find  the duplicates and then based on each duplicate group we need to  keep the duplicate that has max ID column
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