Oracle DB

[Trenton]

How can the request be classified on a specific basis, such as ID 10, 20, 50. I want to fight in order of 10, 50, 20. I got on the Internet, but I couldn't find the answer. ♪ ♪

SELECT
a.department_id, 
b.department_name,
a.job_id
FROM HR.EMPLOYEES a 
LEFT JOIN HR.DEPARTMENTS b
ON a.department_id = b.department_id
WHERE a.department_id = 10
UNION ALL
SELECT

a.department_id,

b.department_name,

a.job_id

FROM HR.EMPLOYEES a

LEFT JOIN HR.DEPARTMENTS b

ON a.department_id = b.department_id

WHERE a.department_id = 50
UNION ALL
SELECT

a.department_id,

b.department_name,

a.job_id

FROM HR.EMPLOYEES a

LEFT JOIN HR.DEPARTMENTS b

ON a.department_id = b.department_id

WHERE a.department_id = 20;

[Avante]

For example, it is possible to do so:

SELECT a.department_id, b.department_name, a.job_id
  FROM HR.EMPLOYEES a 
  LEFT JOIN HR.DEPARTMENTS b
    ON a.department_id = b.department_id
 WHERE a.department_id IN(10, 50, 20)
 ORDER BY decode(department_id, 10, 1, 50, 2, 20, 3)

In fact, for order, we'll replace department_id for the grading number.