SQL
COUNT(), AVG() and SUM() Function
COUNT() Function
COUNT function return number of rows base on given criteria.
Syntax
SELECT COUNT(column_name)
FROM table_name
WHERE condition;
Example
This example will return you the number of records in student table.
SELECT COUNT(studentId)
FROM student;
AVG() Function
AVG function returns average value of a numeric column.
Syntax
SELECT AVG(column_name)
FROM table_name
WHERE condition;
Example
This query will returns you the average fee of the students from student table.
SELECT AVG(Fee)
FROM student;
SUM() Function
SUM function returns total sum a numeric column.
Syntax
SELECT SUM(column_name)
FROM table_name
WHERE condition;
Example
This query will returns you the total fee of the students from student table.
SELECT SUM(Fee)
FROM student;