Please enable Javascript to correctly display the contents on Dot Net Tricks!

Remove duplicate records from a table in SQL Server

 Print 
  Author : Shailendra Chauhan
Posted On : 24 Aug 2012
Total Views : 237,739   
Updated On : 24 Sep 2016
 

Sometimes we required to remove duplicate records from a table although table has a UniqueID Column with identity. In this article, I would like to share a best way to delete duplicate records from a table in SQL Server.

Suppose we have below Employee table in SQL Server.

 CREATE TABLE dbo.Employee
( 
EmpID int IDENTITY(1,1) NOT NULL, 
Name varchar(55) NULL, 
Salary decimal(10, 2) NULL, 
Designation varchar(20) NULL
 ) 

The data in this table is as shown below:

Remove Duplicate Records by using ROW_NUMBER()

 WITH TempEmp (Name,duplicateRecCount)
AS
(
SELECT Name,ROW_NUMBER() OVER(PARTITION by Name, Salary ORDER BY Name) 
AS duplicateRecCount
FROM dbo.Employee
)
--Now Delete Duplicate Records
DELETE FROM TempEmp
WHERE duplicateRecCount > 1 
 --See affected table
Select * from Employee 

For more help about ROW_NUMBER(), please follow the MSDN link.

Summary

In this article, I expose how can you remove duplicate records from a table in SQL Server. I hope after reading this article you will be able to use these tips. I would like to have feedback from my blog readers. Please post your feedback, question, or comments about this article.



Free Interview Books
 
COMMENTS
SUBSCRIBE TO OUR YOUTUBE CHANNEL
 
 
 
LIKE US ON FACEBOOK
 
+