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Mysql order by if condition - wrong order
Posted by: Jan Kowalski
Date: August 22, 2013 07:55AM

Hi everybody, I have a problem with one of my queries.
I got a simple table:

CREATE TABLE `dev_a4a`.`test` ( `id` INT UNSIGNED NOT NULL
AUTO_INCREMENT , `type` VARCHAR(45) NOT NULL , `priority` INT NOT
NULL , PRIMARY KEY (`id`) );

with following rows:

id|type |priority
1 |long |8
2 |long |3
3 |short|9
4 |short|1

I want to get rows ordered by condition:

SELECT (RAND() * priority) as prio, type, priority FROM test
ORDER BY (IF(type = 'short', '2', prio)) DESC, id DESC

As a result I got rows not ordered by if condition. Every time it looks like it's random. Here's one of possible results:

prio | type | priority
'0.05013570194145264', 'long', '8'
'2.9015473750434326', 'long', '3'
'0.320064320527077', 'short', '1'
'7.598900996706356', 'short', '9'

What am I doing wrong?

Expected result:

prio | type | priority
'2.9015473750434326', 'long', '3' <- order by prio
'7.598900996706356', 'short', '9' <- order by common value 2
'0.320064320527077', 'short', '1' <- order by common value 2
'0.05013570194145264', 'long', '8' <- order by prio


------------- EDIT ------------

Ok problem solved:

SELECT CASE WHEN type = 'short' THEN 2 ELSE RAND() * priority END AS prio, type, priority FROM test ORDER BY 1 DESC, id DESC



Edited 1 time(s). Last edit at 08/23/2013 07:25AM by Jan Kowalski.

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