If you can write it as an equation on a white board, that's not complex SQL on a complex database.

Also, it seems pretty clear you probably don't work in a shared responsibility environment.

It doesn't matter how easy to understand the logic might be - it's still a waste of time to have to read and understand every single equation in a script just to know that "Z3" is "subtotals for widgets". The sane person who cares about others reading their code would just use an alias such as "WIDGET_SUBTOTALS".

Using single letter alias' would be like naming API endpoints with single letters.

Oh, right, go read the entire source code if you want to know what enpoint Z3 is, rather than just looking at it's name and selected elements.

It's only logical if the code is only for you.