How can I learn SQL basics?

If you are new to SQL and relational database First : You may need a good introduction to relational database theory books to download : introduction + exercises http://bookboon.com/en/an-introduction-to-relational-database-theory-ebook http://bookboon.com/en/exercises-on-relational-database-theory-ebook Second : You need SQL Basics book or videos that can help book to download : http://www.mediafire.com/download/osxsmq49sntd4vn/SQLServer2008_Arabic.rar Videos on sql found arranged in the following link http://forum.amrkhaled.net/showthread.php?528966 you may find better books or videos but this was a quick search from me .
i usually use msdn which the microsoft development network that contains all what you need , and with any explanation you may ask http://msdn.microsoft.com/en-us/library/bb545450.aspx

Check online, use some blogs, articles...
For more formal source, try to apply for online courses as in or Stanford University online courses.
Best of luck