Aggregate functions include numeric and statistical built-in functions. These topics were covered in more detail in Chapter 9, Working with Expressions. The following is a recap from that chapter.
Understanding aggregate functions
Numeric aggregate functions
Numeric built-in functions handle mathematical calculations. They can all operate on a numeric data type table column or an expression of a numeric data type. The following list shows a sample of these functions:
- AVG: Returns the average of an expression:
- AVG(rating): This will return the average of all the values in a rating column.
- NULL values are ignored.
- COUNT: Returns the number of records:
- COUNT(column1): This will return the count of values in column1 : column1...
