In Need of help with JOIN statement

[cammac]

Hi, could any mysql gurus please help with figuring out if and how it's possible to do the following in a single mysql JOIN query:

 

Select from multiple tables for multiple users the time of the latest update for each user - e.g. tables blog (can be multiple posts), photos (can be multiple photos), profile, interests, etc.:

 

user1 - updated blog - 09-21-2005 12:23:53

user3 - added photo - 09-19-2005 11:34:34

user18 - updated profile - 09-18-2005 09:21:39

 

I tried the above with UNION SELECT but was unable to display only the latest update of each user as GROUP BY gave error.

[cammac]

here's an example of my union select with 2 users:

 

(SELECT id, "updated profile", updated FROM profile WHERE id='18' OR id='19' ORDER BY updated DESC)

UNION

(SELECT id, "posted blog", post_time FROM blog WHERE uid='18' OR uid='19' ORDER BY post_time DESC LIMIT 0,1)

UNION

(SELECT id, "picture added", added_time FROM pictures WHERE uid='18' OR uid='19' ORDER BY added_time DESC LIMIT 0,1) ORDER BY updated DESC

 

when I add "GROUP BY id" to the end or before last "ORDER BY" it gives error