#!/usr/bin/env perl -l

use strict;
use warnings;

use Text::CSV;
use Inline::Files;
use Data::Dump;

my %data;

my $csv = Text::CSV::->new;

while (my $row = $csv->getline(\*CSV1)) {
    @{$data{$row->[0]}}{qw{mem lang}} = @$row[1,2];
}

while (my $row = $csv->getline(\*CSV2)) {
    @{$data{$row->[0]}}{qw{cpu cores}} = @$row[1,2];
}

print 'CSV data merged into hash:';
dd \%data;

print 'Query data: apps with 2 cores:';
print $_ for grep { $data{$_}{cores} == 2 } sort keys %data;

__CSV1__
App1,4,Perl 
App2,8,Java 
App3,8,Java 
App4,4,PHP  
App5,8,C#   
__CSV2__
App1,1.5,2
App2,2.5,4
App3,2.8,4
App4,2.8,2
App5,2.8,2

##</code><code>##

CSV data merged into hash:
{
  App1 => { cores => 2, cpu => 1.5, lang => "Perl", mem => 4 },
  App2 => { cores => 4, cpu => 2.5, lang => "Java", mem => 8 },
  App3 => { cores => 4, cpu => 2.8, lang => "Java", mem => 8 },
  App4 => { cores => 2, cpu => 2.8, lang => "PHP", mem => 4 },
  App5 => { cores => 2, cpu => 2.8, lang => "C#", mem => 8 },
}

Query data: apps with 2 cores:
App1
App4
App5