my $sth = $dbh->prepare($query2);
$sth->execute();
my $employees_loh = $sth->fetchall_arrayref({});

##</code><code>##

$sth->execute($year, $month);
my @array = ();
$sth->bind_col(\(@array));
$sth->fetchall_arrayref({});

##</code><code>##

DBI bind_col: invalid number of arguments: got handle + 0, expected handle + between 2 and 3
Usage: $h->bind_col($column, \$var [, \%attr]) at etc...