Maybe I'm missing something, but I don't believe SQL includes client data rendering. At least not any SQL implementation I've ever worked with. There's always a client that has to interpret SQL data and convert it into a rendered frame as well as send user input back to SQL as a query.
That would seem to be enough of a limitation to 'Doom on SQL' to make the total project... doomed from the start. It remains an interesting exercise in getting SQL to do the rest of it. As long as the code to do so is elegant, it doesn't really matter how Rube Goldberg it gets.
In fact, I might even be more impressed as the SQL gets more convoluted.