Upon first encountering SQL after two decades of Fortran, C, Java, and Python, I thought I had stumbled into hell. I quickly realized that was optimistic: after all, hell has rules.

I have since realized that SQL does too, and that they are no more confusing or contradictory than those of most other programming languages. They only appear so because it draws on a tradition unfamiliar to those of us raised with derivatives of C. To quote Terry Pratchett, it is not mad, just differently sane.

Welcome, then, to a world in which the strange will become familiar, and the familiar, strange. Welcome, thrice welcome, to SQL.

• The Querynomicon: An Introduction to SQL for Weary Data Scientists @ GitHub.