#!/usr/bin/perl

use strict;
use DBI;

my $dbh = DBI->connect( ... );

my @val1_set = qw/foo bar baz quz/;

my $sth = $dbh->prepare("select val1,val2,val3 from atable where val1=?");
my @result_set;

for my $val ( @val1_set ) {
    $sth->execute( $val );
    my $result = $sth->fetchall_arrayref;
    push @result_set, $result;
}
for my $i ( 0 .. $#val1_set ) {
    print "Results for val1=$val1_set[$i]:\n";
    if ( ref( $result_set[$i] ) ne "ARRAY" or
         @{$result_set[$i]} == 0 ) {
        print "__EMPTY_SET__\n\n"
    }
    else {
        for my $row ( @{$result_set[$i]} ) {
            print join("\t", @$row ),"\n"
        }
        print "\n";
    }
}