SQL is a programming language specifically used for relational databases. SQL is not supported by Data Services but provided below are some resources for learning SQL.
Common database management systems (DBMS) include Oracle, PostgreSQL, SQLite, MySQL and Microsoft SQL Server. Each system has its own syntax intricacies but learning standard SQL first should be a good start before learning the specifics of any system. XAMPP is a PHP development enviornment which can be used as a testing enviornment for learning SQL. (See video tutorial below.)
Skillsoft Books is an online collection of computer technology-related ebooks. It contains hundreds of books and videos from respected IT publishers such as MIT Press, Microsoft Press, Osborne/McGraw-Hill, Que, Sams, Sybex and Wiley. Use it to search for a wide variety of books and videos, ranging from beginners level to advanced (Microsoft Word for beginners or an advanced programming language).