Aggregate function

Aggregate functions are use to compute against a "returned column of numeric data" from your select statement.

They basically summarize the results of a particular column of selected data.

Aggregate functions are..

• MIN: returns the smallest value in given column

E.g- SELECT MIN(Marks) As "Lowest marks"

        FROM Exam; 

• MAX: return the largest value in a given column

E.g- SELECT MAX(Marks) As "Highest marks"

        FROM Exam; 

• SUM: returns the sum of the numeric values in a given column

E.g- SELECT SUM(Marks) As "Total marks"

        FROM Exam

        WHERE Marks<35; 

• AVG: returns the average value of a given column

E.g- SELECT AVG(Marks) As "Average marks"

        FROM Exam; 

• COUNT: returns the total number of values in a given column

E.g- SELECT COUNT(Students) 

        FROM Students

        WHERE Marks<35;  

• COUNT(*): returns the number of rows in a table

E.g- SELECT COUNT(*) 

        FROM Students 

        WHERE Marks<35;