Articles about fundamentals
SQL is structured English: the fastest way to learn how to query data
Stop memorizing syntax. If you can ask the question out loud, you can write the query. The Toca dos Dados manifesto, with examples.
fundamentalsbeginner
Why = NULL never works in SQL (and what to use instead)
Your query returns nothing and you swear the data is there. The problem is almost always comparing to NULL with =. Understand it in 3 minutes.
fundamentalsbeginnerpitfalls
The order SQL actually runs your query in (and why it changes everything)
You write SELECT first, but the database runs it last. Understanding the real order of execution explains half the SQL errors that look like magic.
fundamentalsintermediate