[RESOLVED] Selecting Distinct Data in MySQL

[linuxwebshop]

I am working on a "Who is Online" routine. I have an included routine on each page that inserts: the timestamp, the visitor's ip, the page they're on and if they're logged on, their username, otherwise "guest". Like this:

$insert = mysql_query("INSERT INTO $tbl_online (timestamp, ol_user, ip, file)
VALUES('$timestamp', '$ol_user','".$SERVER['REMOTE_ADDR']."','".$SERVER['PHP_SELF']."')")

Now I need to find out how many logged in users are online and display the data (except the timestamp) without repeating. This does not work:

$ol_val = mysql_query("SELECT DISTINCT ol_user, ip, file FROM $tbl_online WHERE ol_user != \"guest\"")
or die("error");
$ol_val_num = mysql_num_rows($ol_val);

This query repeats users that have been on different pages until the timestamp expires. I don't need to worry about the IP, but I need to select unique users & only one file for each.

Any ideas?

[laserlight]

You did not specify the file in the WHERE clause. I note also that a COUNT is possible in the query instead of using mysql_num_rows().

[NogDog]

Maybe use a GROUP BY?

SELECT ol_user, ip, file FROM $tbl_online WHERE ol_user != 'guest' GROUP BY ol_user

[linuxwebshop]

How would I specify the file in the WHERE clause to keep the query from returning multiple results when users have more than one file?

[NogDog]

If you use the GROUP BY option, it would just pick one (not sure if it would be the first it found or the last).

[linuxwebshop]

GROUP BY worked, thanks NogDog!