In Access, the Avg function calculates the arithmetic mean of a set of values in a select query.
The syntax for the Avg function is:
Avg ( expression )
The expression argument represents a string expression identifying the field that contains the numeric data you want to average. Operands in expression can include the name of a table field, a constant, or a function (not one of the other SQL aggregate functions). The average calculated by Avg is the arithmetic mean (the sum of the values divided by the number of values). You could use Avg, for example, to calculate average freight cost.The Avg function doesn’t include any Null fields in the calculation.
In Access, you can use the Avg function in the query design grid, in an SQL statement in SQL view of the Query window, or in an SQL statement within Visual Basic code. It is used in conjunction with the Group By clause.