<?php

	$a = [1,2,3,4,5];
	$b = [2,4,6,7];
	
	$common = array_intersect( $b, $a ); 

	$diff1 = array_diff( $a, $common );
	$diff2 = array_diff( $b, $common );

	print_r( $diff1 );
	print_r( $diff2 );