I got a lot out of Anthony Molinaro's SQL Cookbook, it had a surprising amount of theory in it. It doesn't sound like you're looking for a cookbook type book t

I got a lot out of Anthony Molinaro's SQL Cookbook, it had a surprising amount of theory in it. It doesn't sound like you're looking for a cookbook type book though, what I think you're looking for is books by C.J. Date and Joe Celko.