The summary row provides an easy way to perform basic operations on the data in a column and display the results. The summary row is located at the bottom of table view and at the bottom of simple list fields and related data fields.
You can use the Count function on any type of field. You can use the Sum, Average, Minimum, and Maximum functions on fields of the following types: Number, Currency, Duration, Rating, Automatic Counter, and Calculation (when the result is number, currency, or duration). You can also use the Minimum and Maximum functions on Date and Time fields.