In the following code:
$selectColumns= array('user_id.user_email', // inner join the data from user_id and user_details
             'user_details.first_name', 
             'user_details.last_name');
        $result = $handle->select()->from('user_id', $selectColumns)
                                   ->where('user_id.uid=?', $uid)
                                   ->join('user_details', 'user_id.uid = user_details.uid')
                                   ->query(ZEND_DB::FETCH_OBJ);
Zend selects all the columns in the table, not just the requested ones.
How can I select only some?