I have my complaints about some of the details of the SQL langauge and syntax as well but I don't understand this desire to import features of iterative and fun

I have my complaints about some of the details of the SQL langauge and syntax as well but I don't understand this desire to import features of iterative and functional programming languages into SQL. These are totally different domains and these features don't really cross-over. SQL is a tool for defining what data to pull from a database whereas those features are for more easily decomposing an iterative (or functional) process. Trying to break a complex queries into simpler sub-components (and not have those sub-components act as an optimization barrier) seems like an entirely different kind of problem for which entirely different tools would be required, even if that's not obvious from the outset.