How to delete duplicates on a MySQL table?

Question

I need to DELETE duplicated rows for specified sid on a MySQL table.

How can I do this with an SQL query?

Answer 1

After running into this issue myself, on a huge database, I wasn't completely impressed with the performance of any of the other answers. I want to keep only the latest duplicate row, and delete the rest.

In a one-query statement, without a temp table, this worked best for me,

DELETE e.*
FROM employee e
WHERE id IN
 (SELECT id
   FROM (SELECT MIN(id) as id
          FROM employee e2
          GROUP BY first_name, last_name
          HAVING COUNT(*) > 1) x);

The only caveat is that I have to run the query multiple times, but even with that, I found it worked better for me than the other options.