$result = @mysql_query("DELETE FROM some_table WHERE email_address='$email'");

Delete old records by date

  $result = @mysql_query("DELETE FROM messages_sent WHERE created_date < DATE_SUB(NOW(), INTERVAL 30 DAY)");

  //Also:
  //INTERVAL 1 MONTH
  //INTERVAL 1 HOUR
  //etc

Delete table

Truncate is the fastest method to delete all data in a table as the table is dropped and re-creaed.

$result = @mysql_query("TRUNCATE TABLE all_songs");