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How to query duplicate records and delete duplicate records in MySQL

John Lennon

Apr 11, 2025 pm 05:21 PM

mysql

MySQL query duplicate records using GROUP BY and HAVING conditions; deleting duplicate records can use NOT IN subquery to retain the record with the smallest rowid in the duplicate group.

How to query duplicate records and delete duplicate records in MySQL

MySQL query and delete duplicate records

Query duplicate records

The following SQL queries can be used to find duplicate records:

 <code class="sql">SELECT column_name FROM table_name GROUP BY column_name HAVING COUNT(*) > 1;</code>

The above query will return the duplicate value in the column column_name .

Delete duplicate records

The following SQL queries can be used to delete duplicate records:

 <code class="sql">DELETE FROM table_name WHERE rowid NOT IN ( SELECT MIN(rowid) FROM table_name GROUP BY column_name );</code>

The above query will delete duplicate records, keeping the record with the smallest rowid in each duplicate group.

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