Mapping product options to inventory items

[Dodger]

Hi,

Using information contained in a mySQL database, I'm generating drop down menus containing available product option values.

i.e. 1 Product has 0 or more attributes/options

To get the names (and id's) of the option classes available, I use the following query:

SELECT a.id, a.name
FROM attributes AS a
INNER JOIN product_attributes AS pa
ON a.id = pa.a_id
INNER JOIN products AS p
ON pa.p_id = p.id
WHERE p.id = 1

This would return attribute names/id's for product '1'.

e.g.:
____________
a1 | Color
a2 | Size

Using this data I construct 2 option menus. For each attribute/option class, I use the following statement to retrieve the available attribute values:

SELECT DISTINCT av.id, av.value
FROM attribute_values AS av
INNER JOIN item_attribute_values AS iav
ON iav.av_id = av.id
INNER JOIN items AS i
ON i.id = iav.i_id
WHERE i.quantity > 0
AND av.a_id = {the attr. id}

The output resembles the following:

<form action="/site/order.php" method="post">
<table>
    <tr>
        <td>Color:</td>
        <td>
            <select name="001">
                <option value="0001">Black</option>
                <option value="0002">White</option>
            </select>
        </td>
    </tr>
    <tr>
        <td>Size:</td>
        <td>
            <select name="002">
                <option value="0003">S</option>
                <option value="0004">M</option>
                <option value="0005">L</option>
            </select>
        </td>
    </tr>
</table>
</form> 

Now using the submitted values, I need to identify which item (option value combination), the user wishes to purchase from the item table. (1 product : 1 or M items)

And ideas as to how I could achieve this?

TIA.

(mySQL script attached)