* sql/generics.lisp: add generic function for SELECT.
* sql/objects.lisp: make SELECT a method specialisation.
* sql/classes.lisp: MAKE-QUERY now calls SELECT if the selections
* sql/generics.lisp: add generic function for SELECT.
* sql/objects.lisp: make SELECT a method specialisation.
* sql/classes.lisp: MAKE-QUERY now calls SELECT if the selections