I am not against new ways of querying RDBMSes but until today SQL seems the most simplest and clean way to do it. Most realistic solution will be not to abstract SQL but develop a new query language for relational datasources (on same level with SQL).
I am pro abstractions that simplify things (like TCP) and against naive abstractions ignoring the basic aims of layers under. TCP simplifies things, Clojure-QL complicates them.
PS: The article that you suggested is written by a guy that tend to speculate over his point of view without taking in account the reality. In all modern RDBMSes queries having (a=b and a=c and b=c) will be simplified by query planners (Oracle and Postrgre do it) so there will not be any difference in performance.
PS: The article that you suggested is written by a guy that tend to speculate over his point of view without taking in account the reality. In all modern RDBMSes queries having (a=b and a=c and b=c) will be simplified by query planners (Oracle and Postrgre do it) so there will not be any difference in performance.