In this post, I am sharing two different SQL scripts to delete the all duplicate rows except the one in SQL Server.

Before a few days ago, I was working on a production report and found duplicates records in the few tables. I worked around this and created the different solutions for removing all duplicate rows.

Let’s first create a sample table and data:

CREATE TABLE tbl_RemoveDuplicate
(	
	ID INTEGER PRIMARY KEY
	,Name VARCHAR(150)
)
GO

INSERT INTO tbl_RemoveDuplicate VALUES
(1,'ABC'),(2,'XYZ')
,(3,'XYZ'),(4,'RFQ')
,(5,'PQR'),(6,'EFG')
,(7,'EFG'),(8,'ABC')
GO

First solution is using WITH CTE:

;WITH cteDuplicate AS 
(
    SELECT 
       Name
       ,ROW_NUMBER() OVER (PARTITION BY Name ORDER BY Name) RowNumber
    FROM  tbl_RemoveDuplicate
)
DELETE FROM cteDuplicate
WHERE RowNumber > 1
GO

Second solution is using SELF JOIN:

DELETE FROM A
FROM tbl_RemoveDuplicate AS A
INNER JOIN tbl_RemoveDuplicate AS B
  ON A.Name = B.Name AND A.ID > B.ID
GO

Check your table after remove the duplicates:

SELECT *FROM tbl_RemoveDuplicate ORDER BY ID

--Result:

ID          Name
----------- ------------
1           ABC
2           XYZ
4           RFQ
5           PQR
6           EFG

(5 row(s) affected)