Question

So this seems like a simple little problem, but I haven’t been successful with getting this to work properly. I have a comments table, a posts table, and a notifications table. Previously I stored the postID in a column called “uniqueID” for notifications and for comments. Now I have changed it so that the comments unique id is stored in that column instead. So all I need to do is for each row that is a comment in notifications, go to the comments table where uniqueID==id and then return the value in that table called postID.

Here is a photo showing my question better.

http://i41.tinypic.com/nyzolg.png

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The information from the photo is:

Table: Notifications

id  UserID  FromID  UniqueID    Action  State   Read_Date   Date
1   1       2       1           1       0       0           1325993600
2   1       6       2           1       0       0           1325993615
3   1       2       1           2       0       0           1325993622
4   1       6       2           2       0       0           1325993661
5   2       6       2           2       0       0           1325993661

Action = 1 means UniqueID identifies a row in Posts;
Action = 2 means UniqueID identifies a row in Comments.

Table: Posts

id  ToID    FromID  Post        State   Date
1   1       2       Hey         0       1325993600
2   1       6       okay yeah   0       1325993615

Table: Comments

ID  PostID  FromID  Comment     State   Date
1   1       2       lol         0       1325993622
2   1       6       ohh         0       1325993661

So, in the Notifications table where action is 2, the UniqueID’s are for the ‘id’ in the Comments table.
What I want to return is the PostID, so in the query it would just be as if the UniqueID was this instead:

1
2
1
1
1

But the UniqueID would stay the same where Action is 1.

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My current query is this, and it worked fine before I changed my database values around.

$notificationsq = mysql_query("
SELECT
    N.*,
    P.*,
MAX(N.date) AS newDate
 FROM
    notifications N,
    posts
WHERE
    N.userID='$session'
AND
    (
            (
                   N.action='1'
                AND
                   (N.state = 0 OR N.state=1)
             )
            OR
                N.action='2'
     )
AND P.state='0'
AND
    N.uniqueID=P.id
GROUP BY
    N.uniqueID
ORDER BY
    N.state ASC,
    newDate DESC

") or die(mysql_error());

Answer 1

Try adding “C.*” to your select clause, “comments C” to your from clause, and change ” N.action=’2′” to

(N.action='2' and (N.uniqueId = C.id))