Question

I currently have this

SELECT  *
FROM    images
WHERE   images.id IN (SELECT image_id FROM image_likes WHERE user_id = '1')
    UNION
SELECT * 
FROM images
WHERE images.user_id = '1' AND upload_type in (4,3) ORDER BY id DESC

And this works great, but now i want it to display the most recent results thats have happend.
For example, User A uploaded a image-> information goes into images with a timestamp. User A then likes someone else’s image -> Information goes into image_likes with a timestamp. Now how would i make the two timestamp column’s merge together so i can sort them by DESC.

Breif run over of what the query does.
Selects the image information from images where the user has liked a image in image_likes and then it grabs all of the uploads the user has uploaded from images and merges them into a query. What i need is to be able to sort them using the timestamp from both tables.

Answer 1

how about doing this??

SELECT * FROM (
    SELECT  *
    FROM    images
    WHERE   images.id IN (SELECT image_id FROM image_likes WHERE user_id = '1')
        UNION
    SELECT * 
    FROM images
    WHERE images.user_id = '1' AND upload_type in (4,3) ORDER BY id DESC
) AS a ORDER BY a.timestamp DESC;

OR even better

 (SELECT  *
    FROM images
    WHERE images.id IN (SELECT image_id FROM image_likes WHERE user_id = '1'))
        UNION
 (SELECT * 
    FROM images
    WHERE images.user_id = '1' AND upload_type in (4,3) ORDER BY id DESC)
 ORDER BY timestamp DESC

chk this http://dev.mysql.com/doc/refman/5.5/en/union.html

UPDATE

TRY THIS

 (SELECT images.id, images_likes.timestamp as timestamp FROM images JOIN images_likes 
    ON images.id=image_likes.image_id WHERE user_id = '1')
        UNION
 (SELECT images.id, images.timestamp as timestamp
    FROM images
    WHERE images.user_id = '1' AND upload_type in (4,3) ORDER BY id DESC)
 ORDER BY timestamp DESC

UPDATE

Final query as per your requirement

 (SELECT images.id, images.user_id, images.ext, images.upload_type, images_likes.timestamp as timestamp FROM images JOIN images_likes 
    ON images.id=image_likes.image_id WHERE images_likes.user_id = '1')
        UNION
 (SELECT images.id, images.user_id, images.ext, images.upload_type, images.timestamp as timestamp
    FROM images
    WHERE images.user_id = '1' AND upload_type in (4,3) ORDER BY id DESC)
 ORDER BY timestamp DESC