This chapter continues the study of the more complex Oracle functions and features. Of particular interest here is the creation of simple and group queries that can be turned into views, the use of totals in calculations, and the creation of reports showing a tree structure from one or more tables. Like the techniques covered in Chapter 13, these techniques are not essential for most reporting needs. If they look overly difficult, don’t be frightened off. If you are new to Oracle and the use of its query capabilities, it is enough to know that these capabilities exist and you can turn to them if needed.