finding duplicates?

[viveleroi0]

What query would I use if I want to find duplicate entries of a product ID in the same table? I tried using

SELECT *, a.ID from Products as a, Products as b where a.ID = b.ID

But that returns the entire database, like asking is 1 = 1.

Any ideas? (Using MySQL)

[LordShryku]

Try this

  SELECT product_id, count(id)
    FROM products
GROUP BY product_id
HAVING count(id) > 1