Question

I would like to optimise my Doublon checker if anyone knows how it could be faster.

$doublonchecker="delete bad_rows.* from eMail as good_rows inner join eMail as bad_rows on bad_rows.EMAIL = good_rows.EMAIL and bad_rows.EMAIL_ID > good_rows.EMAIL_ID";
$resultdoublon = mysql_query($doublonchecker);
        if (!$resultdoublon) {
        die('Error : ' . mysql_error());
        }

Answer 1

I usually do it the following way:

Delete from Email where ID not in 
(
Select Min(em.ID) minID
from eMail em  group by em.Email
)