$select = $dbh->prepare(q(select foo, bar from baz));
$delete = $dbh->prepare(q(delete from baz where foo=? and bar=?));
$select->execute();
$select->bind_columns(\($foo, $bar));
while($ref = $select->fetchrow_arrayref()) {
   $delete->execute($foo, $bar) if $foo == 3; #<----this won't work
}