colourfull

$a = [
62 =>[11],
102 =>[654]
];

$b = [
49 => [1,2,3],
62 => [22]
];

foreach($b as $key=>&$value){
foreach( $a as $key2=>$value2){
if($key === $key2){
$value = array_merge($value,$value2);
}
}
unset($value);
}

foreach(array_diff_key($a, $b) as $key=>$value){
$b[$key] = $value;
}