rownum pseudo column in oracle plsql

The ROWNUM is a pseudo column in Oracle SQL / PLSQL which returns a row’s position in the fetched result set.
ROWNUM is evaluated AFTER records are SELECTED from the data-base and BEFORE execution of the ORDER BY clause.

Syntax for the ROWNUM function in Oracle SQL / PLSQL is:

SELECT column(s)
FROM table_name
WHERE ROWNUM < n;

Example 1:
Suppose we have a table named ‘employee’ as shown below:

Employee_Id	Employee_Name	Salary	Department	Commission
101	Emp A	10000	Sales	10
102	Emp B	20000	IT	20
103	Emp C	28000	IT	20
104	Emp D	30000	Support
105	Emp E	32000	Sales	10

If we write out query as:

SELECT *
FROM employee
WHERE ROWNUM <3; 

We will get the following result:

Employee_Id	Employee_Name	Salary	Department	Commission
101	Emp A	10000	Sales	10
102	Emp B	20000	IT	20

Here we can see that the PSEUDO COLUMN ROWNUM has restricted the number of rows in the fetched result to 2.

However ROWNUM always returns no data when used as:
WHERE ROWNUM > n
Or
WHERE ROWNUM BETWEEN n AND m
Or
WHERE ROWNUM IN(a,b,c…n)