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

Suppose you have a table employee, with the following columns:

employee (first_name, last_name, start_date)

In order to delete the rows with a duplicate first_name column:

delete
from employee using employee,
    employee e1
where employee.id > e1.id
    and employee.first_name = e1.first_name