This unique introductory tutorial provides easy-to-understand instructions . It allows you to practice what you learn using the on-line SQL interpreter . You will receive immediate results after submitting your SQL commands . The basics of each SQL command will be covered in this introductory tutorial . Unless otherwise stated, the interpreter will support everything covered in the course. If you want to use the interpreter, use it to help students understand the code pattern and will be able to write /Understand basic SQL codes . For confidential support call the Samaritans on 08457 90 90 90, visit a local Samaritans branch or click here for details . In the U.S. call the National Suicide Prevention LineAuthentication failed. Unique API key is not valid for this user.