Answers for "sort only values but not keys in php"

php sort by associative array value

//php 7+
usort($inventory, function ($item1, $item2) {
    return $item1['price'] <=> $item2['price'];
});

php sort array of array by key

$inventory = [
	['price' => 10.99, 'product' => 'foo 1'],
    ['price' => 5.99, 'product' => 'foo 2'],
  	['price' => 100, 'product' => 'foo 3'],
  
];

$price = array_column($inventory, 'price');

array_multisort($price, SORT_DESC, $inventory);