help with query issue

[EchoFool]

I have two tables

like so:

Usereventtable (in this case has no rows)

UserID | EventID | Complete |

 

and

eventtable (has one row)

EventID | ActivateUrl | Other random fields unrelated to this

  1          bleh.php          etc        etc            etc

 

 

What i am trying to do is, collect all the rows which are found in eventtable but no in usereventtable related to a userID and then pick a random row from that select.

 

How ever it should be finding one row as I purposely put a dummy row in to make sure it works but my mysql_num_rows says it is not finding any row.

 

 

My code:

<?php
$Find = mysql_query("SELECT eventtable.EventID FROM eventtable,usereventtable WHERE eventtable.ActivateUrl='$Url' AND eventtable.EventID != usereventtable.EventID AND usereventtable.UserID='{$_SESSION['Current_User']}' ORDER BY RAND() LIMIT 1")
Or die(mysql_error());
If(mysql_num_rows($Find)<1){
Echo 'failure, check query';
}Else{
Echo 'woo!!';
}
?>

 

What have I done wrong?

[phpzone]

<?php
$Find = mysql_query("SELECT eventtable.EventID FROM eventtable,usereventtable WHERE eventtable.ActivateUrl='$Url' AND eventtable.EventID != usereventtable.EventID AND usereventtable.UserID='{$_SESSION['Current_User']}' ORDER BY RAND() LIMIT 1")
Or die(mysql_error());
If(mysql_num_rows($Find)<1){
Echo 'failure, check query';
}Else{
Echo 'woo!!';
}
?>

 

I'm no SQL expert, but in the absence of any other replies, try something like this if your server support Sub Selects...  or ask in an SQL/Database forum

 

SELECT eventtable.EventID 
FROM eventtable
WHERE eventtable.EventID NOT IN ( SELECT usereventtable.EventID FROM usereventtable WHERE usereventtable.UserID='{$_SESSION['Current_User']}' ) AND eventtable.ActivateUrl='$Url'
ORDER BY RAND() LIMIT 1

[EchoFool]

Ill re-post in the mysql section if some one could delete this thread as to avoid duplicates.