Query of a Query I would think...

Question

So, I have a categories table. It has the name, and then the
subid. If the subid is 0, it is a main category, otherwise it is a
subcategory of the id it holds.
So, if we have books, and that books id is 1. Then we have
non-fiction which is id of 2, but has a subid of 1. There is the
example.
Now for my question. When I output these categories into a
menu list, I want to list the main category so Books followed by
Non-Fiction. So when it outputs into the list menu it looks
somewhat like this.
Books > Non-Fiction
CDs > Rock
Movies > DVD
Where the subid of non-fiction, rock, and dvd is the id of
books, cds, and movies.
Hope that makes sense! Any help would be great.

Answer 1

if you insist on using QoQ, then:
a) 1 QoQ using <cfif> loop in output:
<cfquery name="qryCategories" datasource="mydsn">
SELECT *
FROM tblCategories
ORDER BY name;
</cfquery>
<cfoutput query="qryCategories">
<cfif qryCategories.subid is 0 OR qryCategories.subid is
"">
<cfquery name="qrySubcategories" dbtype="query">
SELECT *
FROM qryCategories
WHERE subid = #qryCategories.id#
ORDER BY name;
</cfquery>
<cfloop query="qrySubcategories">
#qryCategories.name# &gt; #qrySubcategories.name#
</cfloop>
</cfif>
</cfoutput>
or:
b) 2 QoQs:
<cfquery name="qryCategories" datasource="mydsn">
SELECT *
FROM tblCategories;
</cfquery>
<cfquery name="qryMainCategories" dbtype="query">
SELECT * FROM qryCategories WHERE subid = 0 OR subid = ''
ORDER BY name;
</cfquery>
<cfoutput query="qryMainCategories">
<cfquery name="qrySubcategories" dbtype="query">
SELECT *
FROM qryCategories
WHERE subid = #qryMainCategories.id#
ORDER BY name;
</cfquery>
<cfloop query="qrySubcategories">
#qryMainCategories.name# &gt; #qrySubcategories.name#
</cfloop>
</cfoutput>