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

This works for large tables:

 CREATE Temporary table duplicates AS select max(id) as id, url from links group by url having count(*) > 1;

 DELETE l from links l inner join duplicates ld on ld.id = l.id WHERE ld.id IS NOT NULL;

To delete oldest change max(id) to min(id)