#!/usr/bin/perl

# https://perlmonks.org/?node_id=1222256

use strict;
use warnings;

my $ary1 = [
  [ 1,1,1,1,1,'2018-03-01', 'src1', 1,1,1,1 ],
  [ 1,1,1,1,1,'2018-02-15', 'src1', 1,1,1,1 ],
  [ 1,1,1,1,1,'2018-04-11', 'src1', 1,1,1,1 ],
  [ 1,1,1,1,1,'2018-03-11', 'src1', 1,1,1,1 ],
];

my $ary2 = [
  [ 2,2,2,2,'2018-03-02', 2, 'src2', 2,2,2,2 ],
  [ 2,2,2,2,'2018-01-25', 2, 'src2', 2,2,2,2 ],
  [ 2,2,2,2,'2018-04-22', 2, 'src2', 2,2,2,2 ],
  [ 2,2,2,2,'2018-03-22', 2, 'src2', 2,2,2,2 ],
];

my @sorted = map $_->[0],
  sort { $a->[1] cmp $b->[1] }
  map( [ $_, $_->[5] ], @$ary1 ),
  map( [ $_, $_->[4] ], @$ary2 );

use Data::Dump 'dd'; dd \@sorted;

##</code><code>##

[
  [2, 2, 2, 2, "2018-01-25", 2, "src2", 2, 2, 2, 2],
  [1, 1, 1, 1, 1, "2018-02-15", "src1", 1, 1, 1, 1],
  [1, 1, 1, 1, 1, "2018-03-01", "src1", 1, 1, 1, 1],
  [2, 2, 2, 2, "2018-03-02", 2, "src2", 2, 2, 2, 2],
  [1, 1, 1, 1, 1, "2018-03-11", "src1", 1, 1, 1, 1],
  [2, 2, 2, 2, "2018-03-22", 2, "src2", 2, 2, 2, 2],
  [1, 1, 1, 1, 1, "2018-04-11", "src1", 1, 1, 1, 1],
  [2, 2, 2, 2, "2018-04-22", 2, "src2", 2, 2, 2, 2],
]