question about function fetchAllKeyed


    * Fetches results from the database with each row keyed according to preference.
    * The 'key' parameter provides the column name with which to key the result.
    * For example, calling fetchAllKeyed('SELECT item_id, title, date FROM table', 'item_id')
    * would result in an array keyed by item_id:
    * [$itemId] => array('item_id' => $itemId, 'title' => $title, 'date' => $date)
    * Note that the specified key must exist in the query result, or it will be ignored.
    * @param string SQL to execute
    * @param string Column with which to key the results array
    * @param mixed Parameters for the SQL
    * @return array
    public function fetchAllKeyed($sql, $key, $bind = array())
        $results = array();
        $i = 0;
        $stmt = $this->_getDb()->query($sql, $bind, Zend_Db::FETCH_ASSOC);
        while ($row = $stmt->fetch())
            $results[(isset($row[$key]) ? $row[$key] : $i)] = $row;
        return $results;

Above code is from XenForo/Model.php, although there is comment, I still do not understand the usage of $key, Can anyone show me the examples with $key and without $key? In thay way, I can see the difference. Thanks.


in memoriam 1991-2020
Key will return a keyed array versus 0-x as the keys. So if we used this on, say, the user table and set the key to be the user id, you would be able to access my information using:

$keyed = $this->fetchAllKeyed($sql, 'userid');

Without fetchAllkeyed, my information could be stored at say, 74, if they removed 7 of the users before me from teh database. In BBCM, I could do a fetch all keyed on the tag name, and if a user had a tag of "spoiler", I could access it using $codes['spoiler'] versus a number.