Microsoft® Office System Step by Step -- 2003 Edition

Performing Calculations in a Query

You typically use a query to locate all the records that meet some criteria. But sometimes you are not as interested in the details of all the records as you are in summarizing them in some way. As an example, you might want to know how many orders have been placed this year or the total dollar value of all orders placed. The easiest way to get this information is to create a query that groups the necessary fields and does the math for you. To do this, you use aggregate functions in the query.

Access queries support the following aggregate functions:

Function	Calculates
Sum	Total of the values in a field
Avg	Average of the values in a field
Count	Number of values in a field, not counting Null (blank) values
Min	Lowest value ...