Mysql 左加入最新纪录

我看了几个似乎是解决办法的答案，但我很难把我的头绕在它周围

我下面的查询包含到

jos\u payplans\u invoice

和

jos\u payplans\u事务的左连接。
我需要获取该发票的最新发票（
b.invoice\u id
）和最新交易（
c.transaction\u id
）

根据我的理解，我需要子查询，但不确定如何。
感谢您的帮助：-）

谢谢

SELECT 
    a.subscription_id,
    b.invoice_id,
    c.transaction_id 
FROM jos_payplans_subscription AS a 
LEFT JOIN jos_payplans_invoice AS b ON b.object_id = a.order_id 
LEFT JOIN jos_payplans_transaction AS c ON c.invoice_id = b.invoice_id 
GROUP BY a.subscription_id
ORDER BY c.transaction_id DESC

注意:
jos_payplans_invoice.object_id=jos_payplans_subscription.order_id

jos_付费计划_订阅

jos_付款计划_发票

jos_付款计划_交易
这里可能有重构的机会（特别是如果您使用的是支持窗口功能的较新版本的mysql）。不过，这应该会让你大致了解：

为每个
发票\u id

SELECT transaction_id, invoice_id 
FROM jos_payplans_transactions jpt
WHERE create_date = 
    (
        SELECT max(create_date)
        FROM jos_payplans_transactions
        WHERE jpt.invoice_id = invoice_id
    )

获取每个
订单\u id
的最后一个
对象\u id
：

SELECT invoice_id, object_id
FROM jos_payplans_invoice jpi
WHERE create_date = 
    (
        SELECT max(create_date)
        FROM jos_payplans_invoice
        WHERE jpi.object_id = object_id
    )

总而言之：

SELECT
    a.subscription_id,
    b.invoice_id,
    c.transaction_id
FROM jos_payplans_subscription as a
    LEFT OUTER JOIN 
        (
            SELECT invoice_id, object_id
            FROM jos_payplans_invoice jpi
            WHERE create_date = 
                (
                    SELECT max(create_date)
                    FROM jos_payplans_invoice
                    WHERE jpi.object_id = object_id
                )
        ) b on a.order_id = b.object_id
    LEFT OUTER JOIN 
        (
            SELECT transaction_id, invoice_id 
            FROM jos_payplans_transactions jpt
            WHERE create_date = 
                (
                    SELECT max(create_date)
                    FROM jos_payplans_transactions
                    WHERE jpt.invoice_id = invoice_id
                )
        ) c on b.invoice_id = c.invoice_id;

较新版本的Mysql（8.0+）可以处理窗口功能，这将有助于提高性能，因为只需对每个表进行一次扫描：

SELECT
    a.subscription_id,
    b.invoice_id,
    c.transaction_id
FROM jos_payplans_subscription as a
    LEFT OUTER JOIN 
        (
            SELECT invoice_id, 
                object_id, 
                ROW_NUMBER() OVER (PARTITION BY object_id ORDER BY create_date) as rn
            FROM jos_payplans_invoice jpi               
        ) b on a.order_id = b.object_id
            AND b.rn = 1
    LEFT OUTER JOIN 
        (
            SELECT transaction_id, 
                invoice_id ,
                ROW_NUMBER() OVER (PARTITION BY invoice_id ORDER BY create_date) as rn
            FROM jos_payplans_transactions jpt              
        ) c on b.invoice_id = c.invoice_id
            AND c.rn = 1;

您可以尝试以下查询：

SELECT 
    a.subscription_id,
    b.invoice_id,
    c.transaction_id 
FROM jos_payplans_subscription AS a 
LEFT JOIN jos_payplans_invoice AS b ON b.invoice_id = (SELECT max(invoice_id) FROM jos_payplans_invoice WHERE object_id=a.order_id)
LEFT JOIN jos_payplans_transaction AS c ON c.transaction_id = (SELECT max(transaction_id) FROM jos_payplans_transaction WHERE invoice_id = b.invoice_id) 
GROUP BY a.subscription_id
ORDER BY c.transaction_id DESC

让我知道它是否对您有效。
任何人都很难像现在这样帮助您。请记住，这里没有人熟悉您的数据模型（例如，您如何知道哪个记录是最新的？）。如果删除查询中与当前问题无关的部分，您将获得更好的响应，如果您包括一些有代表性的样本数据和您的预期结果。请参考此项。如果有人要求您仅获取您的
jos\u payplans\u transactions
表中每个发票id的最新交易id，而其他什么都没有，您将如何做？@Dyvel-请分享您的表结构，您在问题中提到的三个表的表列。这就足够解决您的问题了。@ishpret:我已经添加了我的表结构：-）谢谢您的解决方案。我正在运行MySQL 5.7-看起来它正在工作，但似乎几乎不可能运行-我的查询已经运行了一个小时了，但还没有完成：-OI猜一些索引可能会有所帮助。这些表上有索引吗？有关
创建日期
、
对象id
、
发票id
和
交易id
的索引应有助于加快速度。