Exam objectives in this chapter:
Work with Data
Query data by using SELECT statements.
Implement aggregate queries.
This chapter focuses on data analysis operations. A data analysis function is a function applied to a set of rows, and it returns a single value. An example of such a function is the SUM aggregate function. A data analysis function can be either a group function or a window function. The two types differ in how you define the set of rows for the function to operate on. You can use grouped queries to define grouped tables, and then a group function is applied to each group. Or, you can use windowed queries that define windowed tables, and then a window function is applied to each ...