$min_cost = min(NULLIF(value, 0))($cost_1, $cost_2, $cost_3, $cost_4);
Some costs on the database return $0.00, so that automatically becomes the $min_cost, even though there is values of more than zero on the other costs
I cant find much info on where the brackets should be on the NULLIF ? anyone help me?
If you don't want to get rid of the 0 entries through SQL, try using array_filter.
array_filter() should get rid of the 0 entries
$array1 = array($cost_1, $cost_2, $cost_3, $cost_4);
$min_cost = min(array_filter($array1));