Question

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我正在创建一个SQL字符串，我得到每个计划的最新订单（只有一个）。

我的SQL字符串现在看起来像这样：

$sql = "SELECT
            o.order_id,
            p.plan_id,
            u.user_id,
            m.module_id,
            c.title AS category_title,
            m.title
        FROM 
            (SELECT
                user_id,
                status,
                order_id,
                payment_method_id,
                time_created
            FROM
                orders
            ORDER BY
                order_id DESC) AS o
        JOIN
            plans AS p
        ON
            p.user_id = o.user_id
        JOIN
            modules AS m
        ON
            p.module_id = m.module_id
        JOIN
            categories AS c
        ON
            m.category_id = c.category_id
        JOIN
            users AS u
        ON
            p.user_id = u.user_id
        WHERE
            p.status = :status
        AND
            p.payment = 0
        AND
            o.status = :status
        AND
            p.subscription_id != ''
        GROUP BY
            p.plan_id";

// Here i get the status variable
$stmt->bindParam(':status', $status, PDO::PARAM_INT);

我想做的是：

$sql = "SELECT
            o.order_id,
            p.plan_id,
            u.user_id,
            m.module_id,
            c.title AS category_title,
            m.title
        FROM 
            (SELECT
                user_id,
                status,
                order_id,
                payment_method_id,
                time_created
            FROM
                orders
            WHERE
                module_id = p.module_id
            AND
                user_id = p.user_id
            LIMIT 1
            ORDER BY
                order_id DESC) AS o
        JOIN
            plans AS p
        ON
            p.user_id = o.user_id
        JOIN
            modules AS m
        ON
            p.module_id = m.module_id
        JOIN
            categories AS c
        ON
            m.category_id = c.category_id
        JOIN
            users AS u
        ON
            p.user_id = u.user_id
        WHERE
            p.status = :status
        AND
            p.payment = 0
        AND
            o.status = :status
        AND
            p.subscription_id != ''
        GROUP BY
            p.plan_id";

我在访问子查询中的p.module_id和p.user_id变量时遇到了很大麻烦。

我的问题是：如何在子查询中访问p.module_id和p.user_id？或者有更好的方法吗？

Answer 1

你不能这样做......试试这个：

$sql = "SELECT o.order_id, p.plan_id, u.user_id, m.module_id, c.title AS category_title, m.title
    FROM 
        (SELECT user_id, status, order_id, module_id, payment_method_id, time_created
           FROM orders ORDER BY order_id DESC) AS o
    JOIN
        plans AS p ON p.user_id = o.user_id
    JOIN
        modules AS m ON p.module_id = m.module_id AND m.module_id=o.module_id
    JOIN
        categories AS c ON m.category_id = c.category_id
    JOIN
        users AS u ON p.user_id = u.user_id
    WHERE
        p.status = :status AND p.payment = 0 AND o.status = :status AND p.subscription_id != ''
        AND p.user_id is not null AND m.module_id is not null
    GROUP BY p.plan_id";

在查询的最后一次尝试使用LIMIT 1 ....

在这里，您希望从订单表中获取记录，其中包含plans的user_id和modules_id的模块，您可以在连接条件中添加这些记录，并确保在主查询的WHERE子句中不是null。因为user_id条件已经存在，所以我只在模块表的连接条件中添加了module_id，在条件中添加了两个。

在sql子查询中访问变量

1 个答案: