Ordering a result set with a column not in result set or queried tables

Sometimes, we need to order a resultset where in we are displaying employee records with a column not in that result set and not even in the table

How can i do that?

You can use such a column in ORDER BY clause that is not in the SELECT clause as long as you have column in the table. Also you can sorting the result set on any expression that is in SELECT clause. you can also concatenate two or more column and use it in order by clause. you can also use column position in ORDER BY clause.

Order by a column that is not appear in SELECT clause:
-----------------------------------------------------

SELECT empno, ename, sal, deptno
FROM emp
ORDER BY hiredate;

Order by Expression:
-------------------
SELECT empno, ename, sal,deptno,'2' sortby
FROM emp
UNION
SELECT empno, ename, sal,deptno,'1' sortby
FROM emp
ORDER BY sortby;

Order by concatenated columns:
--------------------------------
SELECT first_name||' '||Last_name name, salary, deptno
FROM emp_details
order by name;

Order by column position:
------------------------
SELECT empno, ename, sal, deptno
FROM emp
ORDER BY 1,2;

Regards,