[ZPT] Passing where clause to zsql method

[Grant Thibdeau]

My apologies if this is the wrong place to send this to, but here is my 
issue.  This is a beginner ZPT question so I'll give the whole process, 
because I'm not entirely sure if I'm missing a concept here or I'm just 
doing it completely wrong.  I have my ZPT that calls a ZSQL Method which 
gets a list of contact lenses from a SQL DB and renders it.


           <tr tal:repeat="maker root/Lens123/Sql/sqlGetMaker">
             <td><a href="Link"
                    tal:attributes="href NotSure/WheretoLink"
                    tal:content="maker/manufacturer"
                    bordercolor="#FFFFFF"
                    class="NavrBarTextSmall">American
               Hydron</a></td>

           </tr>

So the idea is to have a list of contact lens makers.  This works, now what 
I want to do, is go from my list of lens makers, to a list of actual lenses 
by that maker. So my question now is, how do I pass a maker argument so I 
can search for that specific maker? Do I pass it in the header? Add it as a 
parameter to the PT? Where ever I look on the web, I can only find how to 
do this in DTML and not ZPT.  I understand how it would work if we're 
taking text input from a form, but I don't want to take input from the 
user, I need to make it a link. Then my second question comes up, where 
should I actually make the link to? A python script that calls the zsql 
method, or would I link to a page template which calls the zsql 
method?  Any suggestions would be appreciated or direction to a site that 
has some info about this on it.   Thanks for any time spared

-Grant