Delete All Duplicate Rows or Records from a Table in SQL Server

In this blog, you will learn how to delete all duplicate rows or records from a table in SQL Server

Introduction

 
In this article, you will learn how to delete duplicate rows from a table in SQL Server using the CTE function.
 

SQL query to delete duplicate rows using CTE

 
Let’s create a sample table for the demonstration.
 
 
There are many duplicate rows for Student marks with the same student name and marks.
 
In this statement
  1. WITH CTE AS  
  2. (  
  3.    Select ROW_NUMBER() Over(Partition by StudentName, SubMarks Order by StudentId) as 'RowNumber',*  
  4.    from StudentMark  
  5. )  
  6. Delete from CTE Where RowNumber > 1  
  • First, the CTE uses the ROW_NUMBER() function to find the duplicate rows specified by values in the student name and marks columns.
  • Then, the DELETE statement deletes all the duplicate rows but keeps only one occurrence of each duplicate group.
 

Summary

 
In this article, we have learned how to delete duplicate rows from a table in SQL Server.