note jZed Generally, placeholders can only hold the place of *values*, not structural elements like table and column names and subselect queries. You can (for most DBDs, I believe) use placeholders for values in a subquery so something like this might work: <c> $sth=$dbh->prepare(" UPDATE tableA SET colA =( SELECT colB FROM tableB WHERE colC=? ) WHERE tableA.rec_no=? "); foreach my $row ( @rows ) { $sth->execute( $row->{'tableB.value'}, $row->{'tableA.value'} ) or die $dbh->errstr; } </c> Note that the order of the values in the execute is the order of the placeholders in the SQL, not the order the tables are opened. 659996 659996