MySQL Aggregate Functions:
MySQL has many built-in functions that you can use in SQL statements for performing calculations on combinations of values in databases; these are called aggregate functions. They include such types of basic statistical analysis as counting rows, determining the average of a given column’s value, finding the maximum and minimum value, and so forth.
(1) COUNT( )- Returns the number of rows in a database table.
(2) SUM( )- Returns the total sum of a numeric column.
(3) AVG( )- Calculates the average of a set of values.
(4) MIN( )- Returns the lowest value (minimum) in a set of non-NULL values.
(5) MAX( )- Returns the greatest value (maximum) in a set of non-NULL values.