Question

我有一个invoices表。每张发票都有多个invoice_items和transactions（或者，如果您愿意，还有“付款”）。对于每张发票，我想计算付款金额（即其交易金额的总和）和总金额（即项目金额的总和）。

我写了以下查询：

SELECT 
  invoices.*,
  SUM(transactions.amount_cents) AS amount_paid,
  SUM(invoice_items.quantity * invoice_items.price_cents) AS total
FROM invoices
RIGHT JOIN transactions 
  ON invoices.id = transactions.invoice_id
RIGHT JOIN invoice_items 
  ON invoices.id = invoice_items.invoice_id

但是，由于某种原因，total字段的值乘以交易数量（例如，如果我的总帐金额 20 ，且 2 交易，然后total字段 40 。）

如果我从查询中删除对所有事务的引用：

SELECT 
  invoices.*,
  SUM(invoice_items.quantity * invoice_items.price_cents) AS total
FROM invoices
RIGHT JOIN invoice_items 
  ON invoices.id = invoice_items.invoice_id

正确返回total字段...

我不是真正的专家，所以我可能做了一些非常愚蠢的事情。我已经尝试过不同的JOIN组合，但没有结果。

任何提示？

编辑：半决赛

我试图获取未付的发票，所以这是最后的查询：

SELECT 
  invoices.*,
  SUM(invoice_items.quantity * invoice_items.price_cents) AS total,
t.amount_paid
FROM invoices
LEFT JOIN invoice_items 
  ON invoice_items.invoice_id = invoices.id
LEFT JOIN (
  SELECT 
    invoice_id, 
    SUM(transactions.amount_cents) AS amount_paid
  FROM transactions 
  GROUP BY invoice_id
) t
  ON invoices.id = t.invoice_id
GROUP BY invoices.id
HAVING amount_paid >= total;

编辑：实现后我不需要加入......

我真的不需要获取相关数据。我只是想知道发票是付还是不付。所以我最终使用了一个简单的地方：

SELECT `invoices`.* 
FROM `invoices` 
WHERE (
  (
    SELECT COALESCE(SUM(t.amount_cents), 0)
    FROM transactions t 
    WHERE t.invoice_id = invoices.id
  )
  >=
  (
    SELECT COALESCE(SUM(i.quantity * i.price_cents), 0)
    FROM invoice_items i
    WHERE i.invoice_id = invoices.id
  )
)

但感谢所有帮助过的人。

Answer 1

您可以使用子查询来聚合每个invoice_id最多一行的事务，这样就不会导致额外的行发生。根据卷的不同，您可能希望将子查询配置到临时表中并引用临时表。

SELECT 
  invoices.*,
  SUM(invoice_items.quantity * invoice_items.price_cents) AS total,
t.Amount_Paid
FROM invoices
LEFT JOIN invoice_items 
  ON invoice_items.invoice_id = invoices.id
LEFT JOIN (select invoice_id, SUM(transactions.amount_cents) as Amount_Paid from
transactions group by invoice_id) t
  ON invoices.id = t.invoice_id
GROUP BY invoices.id

Answer 2

您的复制是基于笛卡尔结果...正如您所指出的，一张发票有多个交易，因此交易金额每次存在时都会计算在内。您可能需要来自各个表的子查询，以便按发票ID ...

分组

SELECT 
      invoices.*,
      Payments.Amount_Paid,
      Items.Items_Total
   FROM 
      invoices
         JOIN ( select
                      T.Invoice_ID, 
                      sum( T.amount_cents ) amount_paid
                   from 
                      transactions T
                   group by
                      T.Invoice_ID ) Payments
            on Invoices.id = Payments.Invoice_ID
         JOIN ( select
                      II.Invoice_ID, 
                      sum( II.quantity * II.price_cents) AS Items_total
                   from 
                      Invoice_Items II
                   group by
                      II.Invoice_ID ) Items
            on Invoices.id = Items.Invoice_ID

计算字段的SUM加倍

2 个答案: