This tip is a simple query to remove duplicated entries from a MySQL table.
DELETE FROM table1 USING table1, table1 as table2 WHERE table2.id > table1.id AND table2.unique_param = table1.unique_param
Here I'm using a virtual copy of table1 to check whether it has uniqparam's after the first ocurrence of the _id, and then delete it.
It will only works if you have a sequencial 'id' column.
You can do a select before really deleting to check if it will do the proper thing.