#! /usr/bin/perl
use strict;
use warnings;

use feature qw( say );

my $query = 'foo=123&bar=456';

sub fetch_from_query {
    my $query = shift;
    my @items = @_;

    require URI;
    my $uri = URI->new();
    $uri->query($query);

    my %data = $uri->query_form();

    return @data{@items};
}

say fetch_from_query( $query, 'foo' );

__END__