php sort 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);

To PHP sort array by key, you should use: 
	ksort() (for ascending order) or krsort() (for descending order). 
      
To PHP sort array by value, you will need functions:
	asort() and arsort() (for ascending and descending orders).

ksort(array &$array, int $sort_flags = ?): int