Sources
Fundamentals of Database Systems, Second Edition; Ramez Elmasri, Shamkant B. Navathe; 1994; The Benjamin/Cummings Publishing Company
SQL for Dummies; Allen G. Taylor; 1995; IDG Books Worldwide
http://www.w3schools.com/sql/ (SQL Tutorial)
Fundamentals of Database Systems, Second Edition; Ramez Elmasri, Shamkant B. Navathe; 1994; The Benjamin/Cummings Publishing Company
SQL for Dummies; Allen G. Taylor; 1995; IDG Books Worldwide
http://www.w3schools.com/sql/ (SQL Tutorial)