Different ORDER BY direction for MySql query results - mysql

Question

I am trying to do some ordering on a mysql query that I can't figure out.
id | status | created_at
------------------------
1 | open | 1348778070
2 | closed | 1348711241
3 | open | 1348839204
4 | closed | 1348738073
5 | banned | 1348238422
How do I order the above table so that the 'open' records are first, in ASC order; and then the non-open records are second in DESC order? In another word, have a dynamic second level ordering direction based on some condition?
I have tried a UNION of two SELECT queries with ordering within them, which doesn't work because UNION by default produces an unordered set of rows.
Also I've tried a pseudo column that subtracts the created_at timestamp from a large number, for the closed status records, so I can just ORDER BY ASC to get the result as per below...
SELECT table.*, (table.created_at) as tmp_order FROM table
WHERE table.status = 'open'
UNION
SELECT table.*, (999999999 - table.created_at) as tmp_order FROM table
WHERE table.status = 'closed'
ORDER BY tmp_order ASC
This works but I feel there has to be a better way. Ideally a solution would not include a random big number as above

Answer 1

UPDATED
SELECT *
FROM tmp_order
ORDER BY FIELD(status, 'open') DESC,
CASE
WHEN status = 'open'
THEN created_at
ELSE (999999999 - created_at)
END
or
SELECT *
FROM tmp_order
ORDER BY FIELD(status, 'open') DESC,
CASE
WHEN status = 'open'
THEN created_at END,
CASE
WHEN status <> 'open'
THEN created_at END DESC
Output:
| ID | STATUS | CREATED_AT |
----------------------------
| 1 | open | 1348778070 |
| 3 | open | 1348839204 |
| 4 | closed | 1348738073 |
| 2 | closed | 1348711241 |
| 5 | banned | 1348238422 |
Here is SQLFiddle demo.

Answer 2

Try:
SELECT id, status,
if (status = 'open', created_at, 999999999 - created_at) as tmp_order
FROM table
ORDER BY status, tmp_order

Answer 3

This is how I would solve it:
SELECT
id, status, created_at
FROM
yourtable
ORDER BY
status DESC,
CASE WHEN status='open' THEN created_at END,
CASE WHEN status='closed' THEN created_at END DESC

Answer 4

In your case, you can probably do it in one query, but the general solution, which works for any two different and unrelated. orderings is to use two unioned subqueries each with their own ordering;
SELECT * FROM (
SELECT *
FROM table
WHERE table.status = 'open'
ORDER BY created_at DESC) x
UNION ALL
SELECT * FROM (
SELECT *
FROM table
WHERE table.status = 'closed'
ORDER BY created_at) y