选择不同的选定行

Question

I'm selecting rows from two tables

$a = mysql_query("SELECT a.id, a.id_user, a.id_location,  a.id_event, a.date
FROM    event as a
        LEFT JOIN rating as b
            ON a.id_event = b.id_event AND
                a.id_user = b.id_whos_get_rate
WHERE   a.id_user <> $log1[id] AND
        EXISTS
        (
            SELECT  1
            FROM    event as c
            WHERE   a.id_event = c.id_event AND
                    c.id_user = $log1[id]
        ) AND
        b.id IS NULL ORDER BY DATA") ;

then I'm receiving array

\n\n
 a.id |  a.id_user |  a.id_location |  a.id_event |  a.date \n++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ \n  1 2 1 2 20.03.2013 \n  2 3 1 2 20.03.2013 \n  3 4 1 2 20.03.2013 \n  4 12 1 3 20.03.2013 \n  5 13 1 3 20.03.2013 \n  6 14 1 3 20.03.2013  

Then I want to echo that values and adding radio by each user what I'm doing that way:

 <pre>>while($b = mysql_fetch_array($a)){ >$place = mysql_query("select * from name_event where id=$b[id_location]"); >$place1= mysql_fetch_array($place); >echo $place1[name]; >echo $b[date].; >echo "id event: ".$b[id_event].; >$name= mysql_query("select* from users where id='".$b[id_user]."'and id!=$log1[id]"); >$name1= mysql_fetch_array($name); >if (!empty($name1[login])){ >echo $name1[login]. ; >echo "form method ='post' action ='rate.php' >rate >input type='radio' name='s' value='$name1[id]|1|$b[id_event]' >input type='radio' name='s' value='$name1[id]|2|$b[id_event]' >input type='submit' name='submit' value='value' 

the problem is that a.id_event has multiple values and I have no clue how to change the code to echo only once a.id_event and then all users which taking part in that event because at the moment it's echo

id_event 2 
id_user 2
id_user 3
id_user 4

and I'm expecting to work like that

\nid_event 2  \nid_user 2 \nid_user 3 \nid_user 4 \n

Answer 1

As long as you have your data ordered by the id_event and therefore the values are consecutive, I think the best answer to this would just to have a variable in your loop to contain last's id_event and just print the id_user if it's being repeated.

As an example:

$last_id_event = null;
while($row = mysql_fetch_array($a)){ // Each row
    if($row['id_event'] != $last_id_event){
        echo "id event: ".$row['id_event'];
        $last_id_event = $row['id_event']
    }
    echo "id user: ".$row['id_user'];
}

EDIT: changed foreach to while(... mysql_fetch_array), which is the correct way to go.