Question

I am writing the following query to IBM DB2 server:

SELECT 
    EMPNO, 
    YEAR(CURRENT TIMESTAMP - BIRTHDATE) AS AGE,
    DENSE_RANK() OVER(ORDER BY YEAR(CURRENT TIMESTAMP - BIRTHDATE) ASC) AS RANK

FROM 
    DANDY.EMPLOYEE;

It works, but looks ugly, as I am repeating expression:

YEAR(CURRENT TIMESTAMP - BIRTHDATE)

But writing as follows doesn’t works:

DENSE_RANK() OVER(ORDER BY AGE ASC) AS RANK

How to make it better?

Answer 1

SELECT 
EMPNO, 
AGE,
DENSE_RANK() OVER(ORDER BY AGE ASC) AS RANK
FROM (SELECT EMPNO,
             YEAR(CURRENT TIMESTAMP - BIRTHDATE) AS AGE
      FROM DANDY.EMPLOYEE);