SQL tutorial - http://www.1keydata.com/sql/sql.html
Course Text
Used texts are available for cheap from Amazon: https://www.amazon.com/Database-Concepts-5th-David-Kroenke/dp/0138018804
Reference text: Date, C. J.; An Introduction to Database Systems, 7th ed.; Addison Wesley Longman, Inc.; 2000. (Not required)