RANK(<rank expression>) WITHIN GROUP
(ORDER BY <expression> <ASC|DESC> NULLS <FIRST|LAST>)
 
 
-- Syntax #1 - Used as an Aggregate Function
 
-- As an Aggregate function, the rank returns the rank of a 
-- row within a group of rows. The syntax for the rank function 
-- when used as an Aggregate function is:
 
    RANK( expression1, ... expression_n ) WITHIN GROUP 
     ( ORDER BY expression1, ... expression_n )
 
-- expression1 .. expression_n can be one or more expressions 
-- which identify a unique row in the group.
 
-- The SQL statement below would return the rank of an employee 
-- with a salary of $1,000 and a bonus of $500 from within the 
-- employees table.
 
     SELECT RANK(1000, 500) WITHIN GROUP (ORDER BY salary, bonus)
     FROM employees;
 
-- The syntax for the rank function when used as an Analytic 
-- function is:
 
    RANK() OVER ( [ query_partition_clause] ORDER BY clause )
 
     SELECT employee_name, salary,
     RANK() OVER (PARTITION BY department ORDER BY salary)
     FROM employees
     WHERE department = 'Marketing';