Drilldown Query of Queries

I'm using Coldfusion 9 standalone.

I'm still somewhat new at this, but I found drilldown code that fits my needs for my app. It uses a Query of Queries which to some extent I understand. My problem comes in when I want to take the drilldown a couple of steps further. The first query lists a products that are associated to related sub-products. By clicking a product it will display a list of associated sub-categories. I would then like to link each sub-product to a detail page, but I'm not sure if my sub-product Link code is correct, and I'm not sure what the detail page query should look like to show that specific sub-product detail. Here's the code I have so far:

Product Drilldown Page:

<cfquery name="GetDetail" datasource="mm_instance" cachedwithin="1">
SELECT products.productID, products.product, instance.instances
FROM Products, Instance, ProductInstance
WHERE products.ProductID=ProductInstance.productID AND ProductInstance.instanceID=instance.instanceID
</cfquery>
<cfquery dbtype="query" name="drilldown">
SELECT DISTINCT productID, product
FROM GetDetail
ORDER BY product
</cfquery>

<cfoutput query="DrillDown">
<table width="100%" id="box">
     <tr>
          <td valign="top" width="510" id="prodname"><a href="Inst_List.cfm?ProductID=#DrillDown.ProductID#">#DrillDown.product#<br></a></td>
     </tr>
</table>
</cfoutput>

Sub-Product (or Instance) Drilldown Page:

<cfquery name="GetDetail" datasource="mm_instance" cachedwithin="1">
SELECT products.productID, products.product, instance.instances
FROM products, Instance, ProductInstance
WHERE products.ProductID=ProductInstance.productID AND ProductInstance.instanceID=instance.instanceID
</cfquery>
<cfquery dbtype="query" name="drilldown">
SELECT instances, productID
FROM GetDetail
WHERE GetDetail.productID = #url.productID#
ORDER BY product
</cfquery>

<cfoutput query="DrillDown">
<table width="100%" id="box">
     <tr>
          <td valign="top" width="510" id="prodname"><a href="Inst_Detail.cfm?productID=#DrillDown.productID#">#DrillDown.instances#</a></td>
     </tr>
</table>
</cfoutput>

Sub-Product Detail Page:

Don't know what this query should look like

Thanks!