SQL COUNT(), AVG() and SUM() Functions

            

SQL COUNT(), AVG() and SUM() Functions:

The COUNT() function returns the number of rows that matches a specified criterion.

      SELECT COUNT(column_name) FROM table_name
      WHERE condition;

The AVG() function returns the average value of a numeric column.

     SELECT AVG(column_name) FROM table_name
     WHERE condition;

The SUM() function returns the total sum of a numeric column.

     SELECT SUM(column_name) FROM table_name
      WHERE condition;