Query to delete duplicate records or rows in sql server

Introduction:

In this article I will explain how to delete or remove duplicate records or rows from a datatable in SQL server.

Description:

In previous articles I explained about substring function in SQL server and Replace function in SQL Server and I explained how to delete duplicate records from datatable in asp.net. Now I will explain how to delete duplicate records from a datatable in SQL server. During work with one application I got requirement like get the unique records from datatable in sql server. Actually our datatable does not contain any primary key column because of that it contains duplicate records that would be like this

Actually above table does not contain any primary key column because of that same type of records exist.

Now I want to get duplicate records from datatable for that we need to write query like this

WITH tempTable as ( SELECT ROW_NUMBER() Over(PARTITION BY Name,Position ORDER BY Name) As RowNumber,* FROM EmployeData ) SELECT * FROM tempTable

Once we run above query we will get data like this

If you observe above table I added another column RowNumber this column is used to know which record contains duplicate values based on rows with RowNumber greater than 1.  

Now we want to get the records which contains unique value from datatable for that we need to write the query like this

WITH tempTable as ( SELECT ROW_NUMBER() Over(PARTITION BY Name,Position ORDER BY Name) As RowNumber,* FROM EmployeData ) DELETE FROM tempTable where RowNumber >1 SELECT * FROM EmployeData order by Id asc

Once we run above query all duplicate records will delete from our table and that would be like this

If you enjoyed this post, please support the blog below. It's FREE! Get the latest Asp.net, C#.net, VB.NET, jQuery, Plugins & Code Snippets for FREE by subscribing to our Facebook, Twitter, RSS feed, or by email.

Subscribe by RSS Subscribe by Email