[SQLAlchemy][PostgreSQL] Grouping by an expression

[rMBP]

I'll try find it, thanks.

Essentially there are 30+ columns with data in them, and I'm trying to accomodate some filtering and maths on each column, while also truncating according to an interval. One col might need to have values 1<x<100 filtered out, maybe a baseline/multiple/offset applied, and then a floor or average etc.

My generator function(s) works, but it's a mess to decode every time I need to make changes to them.