A few considerations before building that extremely wide table. Every once in a while, an idea comes along to build a table with a wide array of columns at a particular granularity. This is usually associated with “self-serve analytics” and/or an attempt to define a “source of truth” table. Wide tables, self-serve analytics, and source of truth tables aren’t inherently good or bad… but there are some considerations to this type of table that I’m going to rant about.

An overview of what’s to come: I was originally writing this as a high-level introduction to send people when they encounter things like 6/4 returning 1 instead of 1.5 in some Database Management Systems (DBMS)… overtime its sprawled far beyond that. The points below serve as a TLDR, with a sprawling discussion expanding afterward. Operations like division in SQL can be confusing for novices or anyone without a programming background

The database management system (DBMS) I’ll reference today is Redshift (AWS Cloud Datawarehouse offering) which is based on Postgres. I’ll dive into some of the anti-patterns around Temporary Tables I’ve seen abused during my work experience, why they don’t make sense, and how to fix them. Lets get it out of the way… Temporary Tables are not “better” than Common Table Expressions (CTEs) and CTEs are not “better” than temporary tables.