Ungetestet
$sql = "SELECT * FROM `xy`";
$result = mysql_query($sql, $link);
$meinArray = array();
while ($row = mysql_fetch_assoc($result)) {
foreach ($row as $titel => $wert) {
$meinArray[$titel] = $wert;
}
}
Ich hoffe das es so klappt! 
$_SESSION['ID'] = $row->id;
$_SESSION['Nick'] = $db->escape($user);
$_SESSION['Loggedin'] = true;
$_SESSION['Name'] = $row->name;
$_SESSION['Firstname'] = $row->prename;
$_SESSION['Mail'] = $row->email;
$_SESSION['Primary_Group'] = $row->primary_group;
$_SESSION['Primary_Group_Fields'] = array();
$qry = $db->select(array(
'select' => '*',
'from' => 'groups',
'where' => 'id = ' . $row->primary_group,
));
while($row = $db->fetchAssoc($qry))
{
foreach ($row as $titel => $wert)
{
$_SESSION['Primary_Group_Fields'][$titel] = $wert;
}
}