sub prepex {
    my( $sql, @bindvalues ) = @_;
    my $row;
    eval {
       $row = $dbh->selectrow_arrayref( $sql, {}, @bindvalues );;
       1;
    } or do {
        writeerr( $@ );
        ...;
    };
    return $row->[0] unless wantarray;
    return @$row;
}