how to find average in sql code example

Example 1: sql count

/*COUNT(column_name) will return the number of rows from the column 
that are not NULL*/
SELECT COUNT(column_name)
FROM table_name;

/*COUNT(*) will return the number of rows from the table*/
SELECT COUNT(*)
FROM table_name;

Example 2: sql average

SELECT student_name, avg(notes) FROM student_notes GROUP BY student_name;

Example 3: sql avg()

/*AVG() is an aggregate function that returns the 
   average value for a numeric column*/
SELECT AVG(column_name)
FROM table_name;

Example 4: how to find average in sql

SELECT FIRST_NAME FROM EMPLOYEES
WHERE SALARY = (SELECT AVG(SALARY) FROM EMPLOYEES);

Example 5: above average salary in sql

SELECT FIRST_NAME FROM EMPLOYEES
WHERE SALARY > (SELECT AVG(SALARY) FROM EMPLOYEES);

Example 6: find below average salary in sql

SELECT first_name, salary FROM employees
WHERE salary <= (SELECT AVG(salary) FROM employees);