Start with high-confidence sql & databases books, then narrow by subgenre or adjacent topics.
SQL in 24 Hours, Sams Teach Yourself
Ryan Stephens
T-SQL Fundamentals
Itzik Ben-Gan
Mastering SQL Server 2008
Michael Lee, Gentry Bieker
SQL Tuning
Dan Tow
MySQL Stored Procedure Programming
Guy Harrison, Steven Feuerstein
Data Analysis Using SQL and Excel
Gordon S. Linoff
SQL for Dummies
Allen G. Taylor
SQL for Data Scientists
Renee M. P. Teate
Fundamentals of Database Management Systems
Mark L. Gillenson
SQL All-in-one for Dummies
Allen G. Taylor, Richard Blum
Getting Started With SQL
Thomas Nield
Google Bigquery: the Definitive Guide
Valliappa Lakshmanan, Jordan Tigani
SQL for Data Analysis
Cathy Tanimura
SQL in a Nutshell
Kevin Kline, Regina Obe
The Manga Guide to Databases
Mana Takahashi, Shoko Azuma
Just Use Postgres!
Denis Magda
Learn SQL in a Month of Lunches
Jeff Iannucci
Practical SQL, 2nd Edition
Anthony DeBarros
MySQL Crash Course
Rick Silva
