Apr 14, 2025 · In this article, we will explain the process of deleting duplicate rows from a SQL table step-by-step, using SQL Server, with examples and outputs. We’ll cover techniques using GROUP BY , CTE , and more, incorporating best practices …

Aug 30, 2019 · SQL delete duplicate Rows using Common Table Expressions (CTE) We can use Common Table Expressions commonly known as CTE to remove duplicate rows in SQL Server. It is available starting from SQL Server 2005. We use a SQL ROW_NUMBER function, and it adds a unique sequential row number for the row.

Jul 3, 2017 · To delete the duplicate rows from the table in SQL Server, you follow these steps: Find duplicate rows using GROUP BY clause or ROW_NUMBER() function. Use DELETE statement to remove the duplicate rows.

Nov 25, 2015 · Delete the duplicates from the original table: DELETE t1 FROM t1, holdkey WHERE t1.col1 = holdkey.col1 AND t1.col2 = holdkey.col2 Insert the original rows: INSERT t1 SELECT * FROM holddups btw and for completeness: In Oracle there is a hidden field you could use (rowid): DELETE FROM our_table WHERE rowid …

This article provides a script that you can use to remove duplicate rows from a table in Microsoft SQL Server. There are two common methods that you can use to delete duplicate records from a SQL Server table. For demonstration, start by creating a sample table and data: INSERT INTO original_table values (1)

The following query is useful to delete duplicate rows. The table in this example has ID as an identity column and the columns which have duplicate data are Column1, Column2 and Column3.

Here’s a guide on how to delete duplicate rows in SQL: Identifying Duplicate Rows. Before deleting duplicate rows, you need to identify them. You can use the GROUP BY clause along with the HAVING clause to find rows where certain columns have duplicate values.

Jul 20, 2021 · In this scenario, the ROW_NUMBER () function can be used with a common table expression (CTE) to sort the data then delete the subsequent duplicate records. Check out the examples below to get real world examples on how to delete duplicate records from a table.

Feb 9, 2025 · Let me share the methods I use most often to clean up duplicate data: 1. The Quick Way: Using ROW_NUMBER () This is my favorite method because it’s clean and efficient: SELECT *, ROW_NUMBER() OVER ( PARTITION BY name, email, phone. ORDER BY id. ) as row_num. FROM customers. 2. The Safe Way: Creating a Clean Table.

Dec 6, 2023 · The most common way to remove duplicate rows from our query results is to use the DISTINCT clause. The simplest way to use this is with the DISTINCT keyword at the start of the SELECT list. Suppose we have a table like this: