May I propose, for your long expression of frustration, a simple fix. Don't use left join. Instead select x.x,x.y,y.x,y.z from x,y where x.x=y.z and ...;

This is the same operation but without the screwup syntax. The whole notion of left join style syntax is an abomination and - excepting for those who have internalized it to the detriment of normal discourse - represents needless cognitive load.