Understanding Aggregate Functions

In Day 14, "Using ColdFusion Functions to Manipulate Data," you learned that ColdFusion has a special set of functions that can be used to modify variables or to display certain values, such as a time and date. SQL uses two types of functions: scalar and aggregate. You won't have to worry much about scalar functions because ColdFusion functions will perform the same tricks as SQL's scalar functions, but you'll find SQL's aggregate functions to be pretty useful tools.

Aggregate functions provide "data about the data" selected by SQL statements. That is, aggregate functions are used to report details about the records selected by a given SQL query.

To illustrate how SQL's aggregate functions are used, I added two ...

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