Online PHP editor | output for 3YEK9

<?php $stocks = [ ['product_id'=>2, 'stocks'=>50], ['product_id'=>3, 'stocks'=>100], ['product_id'=>4, 'stocks'=>20], ['product_id'=>5, 'stocks'=>60] ]; $sales = [ ['product_id'=>4, 'quantity'=>3], ['product_id'=>5, 'quantity'=>30] ]; $keyed = array_column($sales, 'quantity', 'product_id'); var_export($keyed); echo "\n---\n"; foreach ($stocks as &$row) { // modify by reference if (isset($keyed[$row['product_id']])) { // search for product_id match $row['stocks'] -= $keyed[$row['product_id']]; // subtract } } var_export($stocks);