SQL Tutorials, subject to verification.

http://baycongroup.com/sql.htm
http://sirius.cs.ucdavis.edu/teaching/sqltutorial
http://www.w3schools.com/sql
http://www.baycongroup.com/tocsql.htm
http://www.dcs.napier.ac.uk/~andrew/sql
http://www.zdnet.com/devhead/stories/articles/0,4413,355971,00.html