<?php
// present inventory and further calculation is done here...
foreach($products_info as $product_info) {
    $result = mysql_query("SELECT product, current_quantity FROM Quantities WHERE product=$product_info['product_id'] AND
                            current_quantity=$product_info['minimum_quantity'];");
    if ($result) {
        $row = mysql_fetch_assoc($result);
        $msg = "Current stock for product $row['product'] is less than minimum stock of $product_info['minimum_quantity']. $current_quantity items are remaining in the stock.";
        mail($recipient, "Stock renewal needed, ", $msg);
    }
}
?>