http://www.perlmonks.org?node_id=462714
Description: Due to an old version of mysql, I had to rewrite a subselect and I decided not to use a join. This is what I cam up with. The subselect looks like this: select object_id from mw_export_record where object_id not in (SELECT object_id from mw_export_record where table_object='advertisers');
my $sth = $dbh->prepare("select object_id from mw_export_record where 
+table_object = 'advertisers'");
$sth->execute();
@results = grep $_, map{ $_->[0] } @{$sth->fetchall_arrayref};
@results = qw/NULL/ if (@results == 0);
$sth = $dbh->prepare("select object_id from mw_export_record where obj
+ect_id not in (" . join(',',  @results) . ")");
$sth->execute();
With special thanks to BUU