Relation

0001-01-01

How to Learn SQL

There’s no secret sauce — learn the two foundations (relations and declarative thinking), then practice in small steps and build from there.

0001-01-01

What is an SQL JOIN?

Forget the set-theory Venn diagrams. A JOIN composes two collections of objects into a new collection that has the properties of both.

0001-01-01

What is an SQL Relation?

A table is a relation with storage. Every SQL query you write defines a new relation, assembled on the fly from relations that already exist.