查询生成器：对关联数据进行多个 SUM 的子查询

Question

我想请求有关使用查询生成器从关联模型中获取多个总和的方法的建议。

共有三个表：

invoices    invoice_items                               payment_receipts
--------    -------------                               -------------
id | name   id| invoice_id  | invoice_qty   unit_price  id| invoice_id  | receipt_amount
===|======  ==========================================  ================================    
 1 |INV01   1| 1            | 1300          |12.00      1 | 1           | 1000
 2 |INV02   2| 1            | 2600          |9.00       2 | 1           | 2000
 3 |INV03   3| 2            | 1100          |15.00      3 | 3           | 900
            4| 3            | 900           |12:00

对于每张发票，我想要项目总金额（数量 * 价格）的总和，以及付款收据的总和。

这个查询（带有子查询）正确地得到了我正在寻找的结果：

SELECT Invoices.id, Invoices.invoice_name, InvoiceItemSum.SumOfAmount, PaymentSum.SumOfPaymentAmount
  FROM Invoices
  INNER JOIN (
    SELECT invoice_id, SUM(Invoice_items.invoice_qty * Invoice_items.unit_price) AS SumOfAmount
      FROM Invoice_items
      GROUP BY Invoice_id
  ) InvoiceItemSum ON InvoiceItemSum.Invoice_id = Invoices.id
  LEFT JOIN (
    SELECT Invoice_id, SUM(Payment_receipts.receipt_amount) AS SumOfPaymentAmount
    FROM Payment_receipts
    GROUP BY Invoice_id
  ) PaymentSum ON PaymentSum.Invoice_id = Invoices.id
WHERE Invoices.invoice_id = 33

我可以直接在我的 CakePhp 应用程序中执行此查询并获得我需要的结果，所以它是这样工作的。

不过，我希望获得有关通过查询生成器执行此操作的更优雅的 CakePHP 方法的建议。

我试过这个：

        $query = $this->Invoices->find()->contain(['InvoiceItems', 'PaymentReceipts']);
        $query->select([
                'Invoices.id',
                'Invoices.invoice_name',
            ]);
        $query->select([
            'total_inv_amt' => $query->func()->sum('InvoiceItems.invoice_qty * InvoiceItems.unit_price'),
            'total_paid_amt' => $query->func()->sum('PaymentReceipts.receipt_amount')
                ])
                ->innerJoinWith('InvoiceItems')
                ->leftJoinWith('PaymentReceipts')
                ->group(['Invoices.id']);
        $query->where(['Invoices.id' => 33]);

但这会导致通过创建此查询将两个总和加倍：

SELECT 
  Invoices.id AS Invoices__id, 
  Invoices.invoice_name AS Invoices__invoice_name, 
  (
    SUM(
      InvoiceItems.invoice_qty * InvoiceItems.unit_price
    )
  ) AS total_inv_amt, 
  (
    SUM(PaymentReceipts.receipt_amount)
  ) AS total_paid_amt 
FROM 
  invoices Invoices 
  INNER JOIN invoice_items InvoiceItems ON Invoices.id = (InvoiceItems.invoice_id) 
  LEFT JOIN payment_receipts PaymentReceipts ON Invoices.id = (PaymentReceipts.invoice_id) 
WHERE 
  Invoices.id = 33 
GROUP BY 
  Invoices.id

我已经按照文档尝试了子查询，但结果不尽如人意。我也玩过连接，但仍然没有骰子。

我的问题是：使用查询生成器编写此查询的好方法是什么？

提前感谢您的任何建议！

Answer 1

你可以通过cakephp JOIN 轻松做到。检查此解决方案，它可能对您有所帮助。直接用编辑器写的，不保证没有语法错误！

$this->Invoices->find()
   ->select([
               'Invoices.id',
               'Invoices.invoice_name',
               'total_inv_amt' => $query->func()->sum('InvoiceItems.invoice_qty * InvoiceItems.unit_price'),
               'total_paid_amt' => $query->func()->sum('PaymentReceipts.receipt_amount')
    ])
    ->join([
            'table' => 'InvoiceItems',
            'alias' => 'InvoiceItems',
            'type' => 'Inner',
            'conditions' => [
                 // your condition for InvoiceItems
             ],
    ])
    ->join([
            'table' => 'PaymentReceipts',
            'alias' => 'PaymentReceipts',
            'type' => 'LEFT',
            'conditions' => [
                // condition for PaymentReceipts
            ],
    ])

Answer 2

好的，在查看了 Alimon 的回答和其他几个关于子查询的问题（例如 and ）之后，我终于找到了正确的查询生成器解决方案。这是：

        $subquery_a = $this->Invoices->InvoiceItems->find('all');
        $subquery_a
            ->select(['totalinvoiceamt' => $subquery_a->func()->sum('invoice_qty * unit_price') ])
            ->where([
                'InvoiceItems.invoice_id = Invoices.id'
            ]);
    
        $subquery_b = $this->Invoices->PaymentReceipts->find('all');
        $subquery_b
            ->select(['totalpaymentamt' => $subquery_b->func()->sum('receipt_amount') ])
            ->where([
                'PaymentReceipts.invoice_id = Invoices.id'
            ]);

        $query = $this->Invoices->find('all')
            ->select([
            'Invoices.id',
            'Invoices.invoice_name',
            'InvoiceItems__total_invoice_amount' => $subquery_a,
            'PaymentReceipts__total_payments_amount' => $subquery_b
            ])
            ->join([
                [
                    'table'     => 'invoice_items',
                    'alias'     => 'InvoiceItems',
                    'type'      => 'INNER',
                    'conditions'=> [
                        'Invoices.id = InvoiceItems.invoice_id'
                    ]
                ]
            ])
            ->join([
                [
                    'table'     => 'payment_receipts',
                    'alias'     => 'PaymentReceipts',
                    'type'      => 'LEFT',
                    'conditions'=> [
                        'Invoices.id = PaymentReceipts.invoice_id'
                    ]
                ]
            ])
            ->group('InvoiceItems.invoice_id');
            $query->where(['Invoices.id' => 33]);

和直接查询的结果是一样的，虽然SQL看起来和手动的有点不一样，但是结果是一样的。

感谢 Alimon 等人的帮助。

查询生成器：对关联数据进行多个 SUM 的子查询

Query Builder: Subquery with multiple SUMs on associated data

cakephp

cakephp-4.x