Question

I am using this function to list items from table helps depending on parameters: (I included most of code but you can really just focus on the mysql querys)

function list_helps($by,$value,$page = -1,$ipp = 20){
    /* Yes I concatenate querys... so i use some variables to help it a bit */
    $sql = 'SELECT helps.* FROM helps ';
    $where = ''; $orderBy = ''; $in = ''; $join = ''; $limit = '';  $resultitems = ''; $header = '';
    if($page > 0)   $limit = 'LIMIT '.$page*$ipp.', '.($page+1)*$ipp; else $limit = 'LIMIT 10';
    switch($by){

        case 'byuser':
            $where = 'WHERE id_user ='.$value;
            $orderBy = 'ORDER BY id DESC';
            break;
        case 'byfriend':
            $sql = 'SELECT
              h.*,
              f.* 
            FROM (
              SELECT
                id,
                CASE followerid WHEN '.$value.' THEN followingid ELSE followerid END AS friend_id
              FROM friends
              WHERE acepted = 1
                AND (followerid  = '.$value.' OR followingid = '.$value.')
            ) AS f
              INNER JOIN helps AS h ON h.id_user = f.friend_id
              ORDER BY h.id DESC';
            break;
        default:
            break;
    }
    $sql .= $where.' '.$orderBy.' '.$limit;
    $res = cache_query($sql,'',60*60*5);
    /* checks in cache first, if not; executes query.. next code it's to render content */
}

There are more cases but lets focus on those two.

They both serve the ‘helps’ that are being requested (if user, or if users’s friend); The problem is when i am trying to retrieve the comments of those (like if it where a blog post); which I am doing like so:

res = cache_query('SELECT help_replies.content, help_replies.date, 
            help_replies.offers, help_replies.accepted, help_replies.id_responds,
            usuarios.first_name, usuarios.last_name, usuarios.avatar,usuarios.id
        FROM help_replies left join usuarios 
            ON  help_replies.id_user = usuarios.id
        WHERE  help_replies.id_responds = '.$this->id.' 
        ORDER BY help_replies.id ASC', '', 30);

foreach($res as $obj) {
    /* $obj['id_responds'] */
    }
}

The thing is that the help_replies.id_responds makes reference to the item, so when the case is ‘byuser’ is fine; but when the case is ‘byfriend’ this field is lost (so is showing always the same comments)

Conclusion:

• byuser -> helps fine & comments fine
• byfriend -> helps fine (which is wierd) & comments wrong

Any Idea why $this->id is not as expected from the (JOINED) query?

-EDIT-

$this->id comes from this construct method (i ommited many atributes)

function __construct($item) {
    $this->id = $item['id'];
    $this->id_user = $item['id_user'];
    ..  
}

And $item is one iteration of the foreach (so its the returned row converted to array)

Muchas Gracias

Answer 1

Your byfriends query executed by function list_helps(...) appears to return a field labelled id twice; once for your helps table and then again for f the alias of the friends table, as part of the sub-query.

I can imagine that if $this->id contains a friends id and not the helps id then your comments query (help_replies) will return the wrong results.

So perhaps changing your sub-query with an alias for the friends id as shown ie id AS friendsId, everything will work as expected?

function list_helps($by,$value,$page = -1,$ipp = 20){
    ...
    ...
    case 'byfriend':
        $sql = 'SELECT
            h.*,
            f.* 
        FROM (
            SELECT
                id  AS friendsId,
                CASE followerid WHEN '.$value.' THEN followingid ELSE followerid END AS friend_id
            FROM friends
            WHERE acepted = 1
            AND (followerid  = '.$value.' OR followingid = '.$value.')
        ) AS f
            INNER JOIN helps AS h ON h.id_user = f.friend_id
            ORDER BY h.id DESC';
        break;

I’ve got into the habit of naming my table identifier field <tablename>Id for this very reason and saves having to use alias everywhere.