How Can I Find and Display Duplicate Records with Full Details in MySQL?

Find Duplicate Records with Expanded Information in MySQL

The MySQL database offers a convenient way to identify duplicate records with the following command:

SELECT address, count(id) as cnt FROM list GROUP BY address HAVING cnt > 1

However, this query only provides a summary of the duplicate records. To obtain detailed information about each duplicate row, consider using the following approach:

We can harness the power of subqueries to accomplish this task. Here's how it can be done:

SELECT firstname,
   lastname,
   list.address
FROM list
   INNER JOIN (SELECT address
               FROM   list
               GROUP  BY address
               HAVING COUNT(id) > 1) dup
           ON list.address = dup.address;

This revised query allows us to extract both the address and the corresponding first name and last name for each duplicate record, resulting in a more comprehensive output. The subquery identifies the duplicate addresses, and the main query then joins the list table with the subquery results to retrieve the complete information for each duplicate row.

By utilizing this approach, we can efficiently identify and display duplicate records with their associated details, eliminating the need for multiple queries and enhancing the readability of the output.

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