SQL

Find and Remove Duplicate Rows in SQL

Identify and safely delete duplicate records from a SQL table based on one or more columns using a Common Table Expression (CTE) and ROW_NUMBER().

WITH CTE_Duplicates AS (
    SELECT
        id,
        column1,
        column2,
        ROW_NUMBER() OVER (PARTITION BY column1, column2 ORDER BY id) as rn
    FROM
        your_table
)
DELETE FROM your_table
WHERE id IN (SELECT id FROM CTE_Duplicates WHERE rn > 1);

How it works: This SQL query uses a CTE with ROW_NUMBER() to identify duplicate rows. It partitions the data by 'column1' and 'column2' (the columns that define a duplicate) and assigns a sequential row number within each partition. Any row with 'rn' greater than 1 is a duplicate, which is then targeted for deletion, keeping one unique record.

Find and Remove Duplicate Rows in SQL

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