what if I gave you a nice little language where you could easily define transforms on tables and explicitly specify 'a where a.key != b.key'. and a type system that would let you define null and all its various arithmetics.

sure, you'd say, but SQL already does all that

but you've have well thought out type construction, and a standard way of defining abstractions and transformations on data. maybe it would be general enough that you would be tempted to go full-on stored procedure and forget about having to juggle two languages and their interface

still no?