how to create the sql_query - php

Question

I have created some filters in php.3 of them are aimming 1 table. The 4th is aimming another table.
first table is :
id_of_orders :
id_order(int) time(NOW) username(varchar) price(decimal)
the second one is :
order :
order_id(int) product(varchar) price (decimal)
order.order_id is refered to the id_of_orders.id_order
Table id_of_orders is like a mapper to the orders table (id_of_orders.id_order has unique numbers).
Table orders contains many orders some of them have same order_id
I want to return the id_of_orders.id_order which contain the order.product=='proion'
The query that i use is this:
$query = "SELECT * FROM id_of_orders WHERE 1=1";
if(!empty($_SESSION['employees']))
$query .= " AND id_of_orders.username='$_SESSION[employees]'";
if(!empty($_SESSION['timis']))
$query .= " AND id_of_orders.price='$_SESSION[timis]'";
if(!empty($_SESSION['dates']))
$query .= " AND DATE(time)='$_SESSION[dates]'";
//if(!empty($_SESSION['proions']))
// $query .= " AND (orders.product='$_SESSION[proions]' && id_of_orders.id_order==orders.order_id)";
$result = mysql_query($query);

Answer 1

You can try a query like
SELECT o.*
FROM id_of_orders i JOIN
(
SELECT order_id
FROM orders
WHERE product = 'proion'
GROUP BY order_id
) q ON i.id_order = q.order_id
WHERE o.username = ?
AND o.price = ?
AND DATE(time) = ?
or
SELECT i.id_order, i.time, i.username, i.price
FROM id_of_orders i JOIN orders o
ON i.id_order = o.order_id
WHERE 1 = 1
AND o.product = 'proion'
AND o.username = ?
AND o.price = ?
AND DATE(time) = ?
GROUP BY i.id_order, i.time, i.username, i.price