VII. Aggregate functions
Aggregate functions are built-in functions that is used
to work with numeric, text and date/time, and currency data. The
aggregate functions include sum, average, count,
maximum, minimum, standard deviation, and variance.
The AVG function is used to calculate average of
field or column that has a number data type, date/time, or currency data type. For
example, find average of unit price column of TblProduct table.
The maximum value of the field or column (number, date/time, or currency data type )can be
calculated by the MAX function. For instance, find the highest price of TblProduct table.
The minimum value of the field or column (number, date/time, or currency data type )can be
calculated by the MIN function. For instance, find the cheapest price of TblProduct table.
The COUNT function use to count row or
record in the table. For example, count products that have quantity greater than twenty.
The SUM function is used to calculate total
value of field or column of a table. For instance, calculate the total
amount of quantity of products starting with letter A.