在嵌套的foreach循环中使用嵌套查询

Question

Okay, after pounding my head against the wall for about 2 hours, I need help. I have a query that pulls "comments" based on a users "followers". The followers have a unique id, and lets say just for ease of use, their id's are 4 and 5. The query returns all followers, so there could be way more than just two rows. That query creates a foreach that I want to say for each "follower" execute this query. Then, that query needs to create a fetch_assoc() so that the data can be recalled later on down the page. The way I have the code right now, it only shows postings from follower 4, and not 5. I have tried using counters to append variable names so that they wont get overwritten each time, but it doesnt help. Thanks a lot!

$sqlb ="SELECT myfriend_ID FROM friends WHERE my_id = '$myuid'";
$resultb = mysql_query($sqlb,$db);
$numa = mysql_num_rows($resultb);
if($numa)
{
    while(($follower = mysql_fetch_assoc($resultb))) {
        $followers[] = $follower;
    }
}
$i=0;
foreach($followers as $follower)
{
    $i++;
    $fnub = $follower['myfollower_ID'];//this will print 4 and 5
    $fnum = $fnub;

    $sql = "SELECT * FROM usr, feed, course WHERE usr.usr_id = '$fnum' AND 
             feed.usr_id = '$fnum' AND course.usr_id = '$fnum' ORDER BY Feed_ID desc";
    $result = mysql_query($sql,$db);
    $num.$fnum = mysql_num_rows($result);
    if($num.$fnum)
    {
        while(($feed = mysql_fetch_assoc($result))) {
            $feeds[] = $feed;
        }
        foreach($feeds as $feed)
        {
            echo $feed['comment'];
        }
    }
}

Answer 1

$sqlb ="SELECT myfriend_ID FROM friends WHERE my_id = '$myuid'";
$resultb = mysql_query($sqlb,$db);
$follower = array();

if(mysql_num_rows($resultb))
{
   while(($follower = mysql_fetch_assoc($resultb))) {
      $fnum = $follower['myfriend_ID'];//what is the column name
      $sql = "SELECT * FROM usr, feed, course WHERE usr.usr_id = '$fnum' AND feed.usr_id = '$fnum' AND course.usr_id = '$fnum' ORDER BY Feed_ID desc";
      $result = mysql_query($sql,$db);
      if( mysql_num_rows($result))
      {
         while(($feed = mysql_fetch_assoc($result))) {
           echo $feed['comment'];
       }
    }
}

And you must combine these two queries into single. But I am not too good in SQL. Probably some one other can help.

Answer 2

You assign $i, then you increment $i within the foreach, but you never use $i for anything else, I'm not sure what that counter is supposed to do. I'm unsure of why you assign a second variable to the value of $fnub, why not just use $fnub each time? Later you use (what we can only assume is) an empty $num variable and prepend $fnum with it - I'm not sure why - or even why you have to assign anything to the num rows, just use the function within the if as that looks to be the only instance you are using $num.$fnum.

You can take your last foreach out completely and move the content of that loop into the while before it as they both are iterating over the same data, just assign the values, then echo $feed['comment'] out right there, then it will move the pointer and have the next value ready for you by itself.