What is an aggregate function?

Answer: To aggregate means to put together or combine. An aggregate function, therefore, performs a calculation on the values in a column and returns a single (combined) value, such as a count or an average. Examples of using this type of function are as follows:

?Finding the sum (total) values in a column. Example: the total amount contributed to a specific fund.
?Obtaining a count of a set of records. Example: the total number of 18-year-old members in an organization.
?Determining the average value in a column. Example: the average dollar amount of pledges made to a specific fund.
?Finding the lowest value in a column. Example: the lowest contribution amount made to a specific fund.
?Finding the highest value in a column. Example: the oldest member in your organization.
In each example, all you want is a summary of the column's data—not the column's actual data. Therefore, the query result is always equal to 1.