Question

我有以下查询，我想通过UserView ID降序排序，看起来像是非常基本的问题，但我无法弄清楚如何做到这一点，我想继续选择用户。*现在，但由UsersView订购表主键desc，有什么想法吗？

 $phql = " SELECT *
                      FROM User
                      WHERE user_id IN
                      ( SELECT user_to
                        FROM UsersView
                        WHERE user_from=:user_to: )
                      AND gender!=:gender:
                      AND user_id NOT IN (".implode(",",$this->user->getBlocked()).")
                      ORDER BY last_visit DESC
                 /* order by should be usersview.id DESC */ 
                      ";

运气好吗？

Answer 1

根据您的数据模型，您可以对UsersView进行额外的连接，以便您可以在ORDER BY子句中使用它的id列。

 $phql = " SELECT *
                  FROM User
        JOIN UsersView on User.user_id = UsersView.user_to
                  WHERE user_id IN
                  ( SELECT user_to
                    FROM UsersView
                    WHERE user_from=:user_to: )
                  AND gender!=:gender:
                  AND user_id NOT IN (".implode(",",$this->user->getBlocked()).")
                  ORDER BY UsersView.id DESC";

您也可以避免使用嵌套选择来执行过滤，并使用连接表来代替过滤器：

 $phql = " SELECT *
                  FROM User
        JOIN UsersView on User.user_id = UsersView.user_to
                  WHERE user_from=:user_to:
                  AND gender!=:gender:
                  AND user_id NOT IN (".implode(",",$this->user->getBlocked()).")
                  ORDER BY UsersView.id DESC";

Answer 2

你的问题确实没有足够的信息来回答这个问题，这就是为什么有人要求你的桌子结构。

我相信我知道你在问什么，所以我会猜测＆＃39;在你的桌子结构。以下是我认为将使您走上正确道路的结构，数据和解决方案。我也删除了PHP，因为它与你的问题无关。

CREATE TABLE `User` (user_id int, gender varchar(1));
CREATE TABLE UsersView (user_to int, user_from int, last_visit datetime);

INSERT INTO `User` VALUES
(1, 'M'),(2, 'F'),(3, 'M'),(4, 'F'),(5, 'F');

INSERT INTO UsersView VALUES
(2, 1, CURRENT_TIMESTAMP),
(3, 1, CURRENT_TIMESTAMP),
(4, 1, CURRENT_TIMESTAMP),
(5, 1, CURRENT_TIMESTAMP),
(1, 2, CURRENT_TIMESTAMP),
(3, 2, CURRENT_TIMESTAMP),
(4, 2, CURRENT_TIMESTAMP),
(5, 2, CURRENT_TIMESTAMP),
(1, 3, CURRENT_TIMESTAMP),
(2, 3, CURRENT_TIMESTAMP),
(4, 3, CURRENT_TIMESTAMP),
(5, 3, CURRENT_TIMESTAMP),
(1, 4, CURRENT_TIMESTAMP),
(2, 4, CURRENT_TIMESTAMP),
(3, 4, CURRENT_TIMESTAMP),
(5, 4, CURRENT_TIMESTAMP);                      


SELECT u.user_id, max(v.last_visit)
FROM User u
LEFT OUTER JOIN UsersView v ON u.user_id = v.user_to
WHERE u.user_id IN (
    SELECT user_to
    FROM UsersView
    WHERE user_from=1
)
AND u.gender != 'M'
AND u.user_id NOT IN (1)
GROUP BY u.user_id
ORDER BY max(v.last_visit) DESC;

MySQL - PHP由Inner Joining表id而不是Selected表ID排序？

2 个答案: