In the chapter we looked at some of the advanced features of SQL, including all the different types of joins: inner, left outer, right outer, and full outer. Star joins, which are used in support of star schemas, were also examined.

SQL can become very useful for solving complex business problems by using such features as CASE expressions, nested table expressions, UNIONs and subqueries. These features allow us to push a lot of business logic into the SQL statement.