I can recommend "SQL Queries for Mere Mortals: A Hands-on Guide to Data Manipulation in SQL" as a good general SQL book.
From: Scott Ribe <scott_ribe@elevated-dev.com> To: Postgresql General <pgsql-general@postgresql.org> Sent: Wednesday, 23 January 2013, 22:56 Subject: [GENERAL] seeking SQL book recommendation
For a client who needs to learn how to query the db:
- No SQL knowledge at all; needs to start from square 1.
- Smart, capable person, who will be in this position for a long time, using this db for a long time.
- No chance in hell this db will be moved off PG, so PG-centric is fine ;-)