Fundamentals of Query Tuning

You’ve finished my free How to Think Like the Engine class, and now you wanna take it up a notch.

You’re confident writing queries to get the data you want, and you’ve been doing it for a couple of years. You took an intro course when you first got started, and sure, you learned select/from/where/group-by – but how do you make your queries go faster?

In this course, you’ll learn:

  • How sp_BlitzCache shows you which queries to focus on, and what parameters to use with sp_BlitzCache to guarantee the best bang for the buck on your own SQL Server
  • How to read an execution plan to find the problems in a query
  • What parts of estimated, cached, and actual plans are lying to you
  • How to identify common anti-patterns in queries and plans, and fix ’em fast

Recent changes for this class: 2026-07-16: First live class rotation for 2026! Lots of changes:

  • “How SQL Server Builds Query Plans” chapter – remixed from a combination of Fundamentals & Mastering material.
  • “Good Defaults for New Apps” chapter – all new
  • “Tools to Improve Cardinality Estimation” chapter – remixed from a combination of Fundamentals & Mastering material.
  • “Lab – Improve Cardinality Estimation” chapter – adapted from a former Mastering Query Tuning lab.

Even if you’ve been through Fundamentals of Query Tuning before in prior years, you’re going to want to restart this one from scratch.

Introductions