A function that performs a computation on a set of values rather than on a single value, to calculate group-level totals and statistics. For example, finding the average or mean of a list of numbers is an aggregate function.
All database management and spreadsheet systems support a set of aggregate functions that can operate on a set of selected records or cells.
Aggregate functions perform calculations over a series of values, such as the columns retrieved with a SELECT statement. These include AVG(), COUNT(), MAX(), MIN(), SUM().