[Zope] SQL query results as <dtml> values ?

Maybe my question was too dense. I will try again. lets say I do this in a ZSQL method SELECT * FROM foo; of course I get a table of results. Now can I some how run another query base on the results, like to do an UPDATE and have the <dtml-sqlvar type=blah> use the values from the table ? Please, I just need a little help here. Thanks Richard