You likely learned the mechanics of writing basic SQL in a relatively short period of time. Throughout the course of a few weeks or few months, you became comfortable with the general statement structure and syntax, how to filter, how to join tables, and how to group and order data. But, how far beyond that initial level of proficiency have you traveled? Writing complex SQL that executes efficiently is a skill that requires you to move beyond the basics. Just because your SQL gets the job done doesn’t mean it does the job well.
In this chapter, I’m going to raise the hood and look at how SQL executes from the inside out. ...