Best book to learn about SQL and databases?

To add to suggestions of others, the SQL Antipatterns was also an insigtful read about basic pitfalls of db design.

I have also found first chapters from Designing Data Intensive Applications helpful to get context around sql/nosql dbs.

I like Practical SQL from No Starch Press: https://nostarch.com/practicalSQL

I didn't learn from the book myself, but I read it to evaluate it as a teaching tool for juniors and wound up recommending it.

I took Neil Sainsbury’s Mastery with SQL course and would recommend it.