"Perfectly intelligent programmers often struggle when forced to work with SQL. Why? Joe Celko believes the problem lies with their procedural programming mindset, which keeps them from taking full advantage of the power of declarative languages. The result is overly complex and inefficient code, not to mention lost productivity."
It's helping you write queries by auto formatting and good auto completion.
Also, leading a new line with the comma.
In all the algebra classes I've taken, one nice thing about sets is you can arrange them in any order you like, and you'll get the same answer any way you slice it. There's no inherently correct orientation of mathematics. That's kind of the point. It's fully generic, by default. "x" can mean anything (at least, in the algebraic structure we've assumed).
With SQL, the experts drone "think in sets!" as a way to mean "you happened to pick a different order than me, so your query will run 1000 times slower". Well, mine is still sets. I'm not writing a for-loop here (and I'm pretty sure my SQL dialect has those by now).
I've actually had the most luck with SQL by thinking about it in terms of looping first. Figure out the most efficient loop over your biggest table, and then write a query in a way that makes it easy for the optimizer to loop over that.
Then again, nobody ever accused me of being "perfectly intelligent".
PostgreSQL has great documentation, and I will give it a serious read one day.