$subQuery = $dao->field("u.*,ub.aaa")
                            ->alias("as u")
                            ->join($relationType.' __USER_BIND__ AS ub ON u.id = ub.user_id')
                            ->where($where)
                            ->group("u.id")
                            ->select(false);会这个效果：（加了两次别名，报错）
SELECT COUNT(*) AS tp_count FROM ( SELECT u.*,ub.aaa FROM ly_user as u as u LEFT JOIN ly_user_bind AS ub ON u.id = ub.user_id GROUP BY u.id ) as tmp LIMIT 1


另一种写法：（解决）        
$subQuery = $dao->table("__USER__ AS u ")->field("u.*,ub.aaa")
        ->join($relationType.' __USER_BIND__ AS ub ON u.id = ub.user_id')
        ->where($where)
        ->group("u.id")
        ->select(false);SELECT COUNT(*) AS tp_count FROM ( SELECT u.*,ub.aaa FROM ly_user AS u LEFT JOIN ly_user_bind AS ub ON u.id = ub.user_id GROUP BY u.id ) as tmp LIMIT 1