Question

我正在尝试做一些我认为非常简单但却无法在SQL语句中弄明白的事情。表格

发票（列 - GrossAmount）
收据（列 - 收据价值，可能有收据或根本没有收据）
信用票据（列 - GrossCredit，可能有信用票据或无信用证）

我想显示未结帐单总额，即显示Invoices.GrossAmount > (sum(Receipt.ReceiptValue) + sum(CreditNotes.GrossCredit))所有发票。

查询需要显示所有未完全支付或根本未支付的发票。

InvoiceId在所有表中都与外键相同。

使用MS SQL Server 2014。

Answer 1

您需要单独对每个表进行求和（按发票分组），然后[左]加入结果：

SELECT i.InvoiceId
FROM   invoices i
LEFT JOIN (SELECT   InvoiceId, SUM(ReceiptValue) AS sum_receipt
           FROM     receipts
           GROUP BY InvoiceId) r ON i.InvoiceId = r.InvoiceId
LEFT JOIN (SELECT   InvoiceId, SUM(GrossCredit) AS sum_credit
           FROM     credit
           GROUP BY InvoiceId) g ON i.InvoiceId = g.InvoiceId
WHERE     i.GrossAmount > COALESCE(sum_receipt, 0) + COALESCE(sum_credit, 0)

Answer 2

我想你想要这样的东西：

select i.*,
       coalesce(r.sumrv, 0) as receiptValue,
       coalesce(c.sumgc, 0) as grossCredits
from invoices i left join
     (select invoiceId, sum(receiptvalue) as sumrv
      from receipts
      group by invoiceId
     ) r
     on i.invoiceId = r.invoiceId left join
     (select invoiceId, sum(grosscredit) as sumgc
      from credits c
      group by invoiceId
     ) c
     on i.invoiceId = c.invoiceId 
where i.GrossAmount > coalesce(r.sumrv, 0) + coalesce(c.sumgc, 0);

三件重要的事情：

使用left join，这样就不会删除一个或两个表中没有匹配记录的发票。
使用coalesce()，以便将NULL值视为0。
在加入表格之前进行聚合。

从两个表中求和并与第三个表中的值进行比较

2 个答案: