General  
Calculates the rank of a value in a group of values. Rows with equal values for the ranking criteria receive the same rank. Oracle then adds the number of tied rows to the tied rank to calculate the next rank. Therefore, the ranks may not be consecutive numbers.  
Aggregation  
As an aggregate function, RANK calculates the rank of a hypothetical row identified by the arguments of the function with respect to a given sort specification. The arguments of the function must all evaluate to constant expressions within each aggregate group, because they identify a single row within each group. The constant argument expressions and the expressions in the ORDER BY clause of the aggregate match by position. Therefore, the number of arguments must be the same and their types must be compatible.  
Single Column RANK as Aggregation Function 
RANK(<rank expression>) WITHIN GROUP (ORDER BY <expression> <ASCDESC> NULLS <FIRSTLAST>) 
conn hr/hr  the following query returns the rank for a $15,500 salary SELECT RANK(15500) WITHIN GROUP (ORDER BY salary DESC NULLS LAST) SAL_RANK FROM employees; 

Multiple Column RANK as Aggregation Function 
RANK(<rank expression>) WITHIN GROUP (ORDER BY <expression> <ASCDESC> NULLS <FIRSTLAST>) 
The following query returns the rank
of a hypothetical employee with a salary of $15,500 and a commission of 3.6% conn hr/hr SELECT RANK(.36, 15500) WITHIN GROUP (ORDER BY commission_pct, salary) RANK FROM employees; 

Multiple Column RANK as Aggregation Function 
RANK(<rank expression>) WITHIN GROUP (ORDER BY <expression> <ASCDESC> NULLS <FIRSTLAST>) 
The following query returns the rank
of a hypothetical employee with a salary of $15,500 and a commission of 3.6% conn hr/hr SELECT RANK(.36, 15500) WITHIN GROUP (ORDER BY commission_pct NULLS FIRST, salary) RANK FROM employees; 

Analytic  
As an analytic function, RANK computes the rank of each row returned from a query with respect to the other rows returned by the query, based on the values of the value_exprs in the order_by_clause.  
RANK Analytic Function 
RANK() OVER (<order by clause>) 
 find the employee with the
2nd
highest salary conn hr/hr SELECT * FROM ( SELECT employee_id, last_name, salary, RANK() OVER (ORDER BY salary DESC) EMPRANK FROM employees) WHERE emprank = 2;  verify result SELECT employee_id, last_name, salary, RANK() OVER (ORDER BY salary DESC) EMPRANK FROM employees; 

 find the 20 largest tables
in a tablespace conn / as sysdba col segment_name format a30 SELECT * FROM ( SELECT segment_name, blocks, RANK() OVER(ORDER BY blocks DESC) SZ FROM dba_segments WHERE segment_type = 'TABLE' AND TABLESPACE_NAME = 'UWDATA') WHERE SZ < 21; 

RANK Analytic Function 
RANK() OVER (<query partition clause> <order by clause>) 
conn hr/hr SELECT department_id,last_name,salary,commission_pct, RANK() OVER (PARTITION BY department_id ORDER BY salary DESC, commission_pct) RANK FROM employees; SELECT department_id,last_name,salary,commission_pct, RANK() OVER (PARTITION BY department_id ORDER BY salary DESC, commission_pct) RANK FROM employees WHERE department_id = 80; 
Other Related Topics 
Numeric Functions 