An Oldie but a Goodie to an Intermediate Level,
This review is from: Lan Times Guide to SQL (Paperback)
With 5 other SQL titles on my shelf, plus docs from Sybase, Oracle & MS SQL Server, this is the book I (almost) always grab first.
Well-organized and well-written, an excellent walk-through of "the basics" and as a syntax reference with good examples.
Look elsewhere however for advanced administration and optimization techniques (Celko's SQL for Smarties is good in this regard). Consider this book as best for Beginner-to-Intermediate topics.