SQL JOIN,GROUP BY在三个表上获取总计

前端之家收集整理的这篇文章主要介绍了SQL JOIN,GROUP BY在三个表上获取总计前端之家小编觉得挺不错的,现在分享给大家,也给大家做个参考。
我继承了以下数据库设计.表是:
  1. customers
  2. ---------
  3. customerid
  4. customernumber
  5.  
  6. invoices
  7. --------
  8. invoiceid
  9. amount
  10.  
  11. invoicepayments
  12. ---------------
  13. invoicepaymentid
  14. invoiceid
  15. paymentid
  16.  
  17. payments
  18. --------
  19. paymentid
  20. customerid
  21. amount

我的查询需要返回给定客户编号的invoiceid,发票金额(在发票表中)和应付金额(发票金额减去对发票的任何付款).客户可能有多张发票.

当对发票进行多次付款时,以下查询为我提供了重复记录:

  1. SELECT i.invoiceid,i.amount,i.amount - p.amount AS amountdue
  2. FROM invoices i
  3. LEFT JOIN invoicepayments ip ON i.invoiceid = ip.invoiceid
  4. LEFT JOIN payments p ON ip.paymentid = p.paymentid
  5. LEFT JOIN customers c ON p.customerid = c.customerid
  6. WHERE c.customernumber = '100'

我怎么解决这个问题?

解决方法

我不确定我有你,但这可能是你想要的:
  1. SELECT i.invoiceid,sum(case when i.amount is not null then i.amount else 0 end),sum(case when i.amount is not null then i.amount else 0 end) - sum(case when p.amount is not null then p.amount else 0 end) AS amountdue
  2. FROM invoices i
  3. LEFT JOIN invoicepayments ip ON i.invoiceid = ip.invoiceid
  4. LEFT JOIN payments p ON ip.paymentid = p.paymentid
  5. LEFT JOIN customers c ON p.customerid = c.customerid
  6. WHERE c.customernumber = '100'
  7. GROUP BY i.invoiceid

如果每张发票有多个付款行,这将获得金额总和

猜你在找的MsSQL相关文章