Finding if a module is installed in a store

[wcw]

Is there an efficient way to find if a module is installed in a store? Looking up a module code in modules database, retrieving the module:id, then looking up that module:id in the store modules database is not very efficient.

[MichaelBrock]

That's the method I use. The only more efficient method that occurs to me would be a mysql/mivasql statement to join the modules and storemodules databases in a single view.