Question

刚刚开始实习并且已经完成了一些SQL任务。发现它有点棘手。感谢任何帮助。谢谢！

任务：

“是否可以为以下内容撰写提醒。显示所有客户，当下个月到期的未结销售订单与开放式销售发票合并（添加）时，超出其信用额度。”

我建议的逻辑：

首先，我要做的是在下个月内为每个客户（在SALES表中）汇总所有销售订单。
接下来，为每个客户汇总所有未结发票，即计算每个客户欠款的总金额（在INVOICES表中）。
然后我想通过相应的customer_id将1和2的结果加在一起
接下来比较上面3中的计算，看看它是否大于每个客户的信用额度。

如果3中的总和超过信用额度，则只应在生成的表格中显示这些公司。结果表的理想格式是

Cust_ID|Name|Sum_sales_orders (1.above)|Sum_open_invoices (2.above)| Total_orders&invoices
----------------------------------------------------------------------------
   1   |  A |  25000                   |  333                      | 25333 
       |    |                          |                           |

到目前为止我的代码是

 SELECT arc.company, arc.credit_limit, 
     sum (ard.unit_price * ard.invoice_qty) as open_invoice_total, 
     sum (od.total_qty_ord * od.unit_price) as open_orders_total
 FROM iqms.arprepost_detail ard, iqms.arprepost arp, iqms.arcusto arc, iqms.ord_detail od, iqms.orders o
 WHERE ard.arprepost_id = arp.id 
     and arc.id = o.arcusto_id and o.id = od.orders_id
     and arp.arcusto_id = arc.id
  GROUP BY arc.company, arc.credit_limit

我认为这是在sum（）函数中计算正确的总数？或者我错了？如何添加open_invoice_total和open_orders_total？然后将它们与credit_limit进行比较？

我希望你们明白我要做的事情。我在这里先向您的帮助表示感谢！：）

Answer 1

您可以使用HAVING子句检查总计的总和是否超过信用额度，如此。为了便于阅读，我还用INNER JOINS替换了WHERE子句中的连接。

 SELECT arc.company, arc.credit_limit, 
       sum(ard.unit_price * ard.invoice_qty) as open_invoice_total, 
       sum(od.total_qty_ord * od.unit_price) as open_orders_total
 FROM iqms.arprepost_detail ard 
        INNER JOIN iqms.arprepost arp ON ard.arprepost_id = arp.id
        INNER JOIN iqms.arcusto arc ON arp.arcusto_id = arc.id
        INNER JOIN iqms.ord_detail od ON o.id = od.orders_id
        INNER JOIN iqms.orders o ON arc.id = o.arcusto_id 
  GROUP BY arc.company, arc.credit_limit
  HAVING sum(ard.unit_price * ard.invoice_qty) + sum(od.total_qty_ord * od.unit_price) > arc.credit_limit;

修改

为了澄清Dems评论，GROUP BY不允许aliases的规范，因此上述查询'重复'SELECT和HAVING中的总和}。这可以通过嵌套来消除，但请注意HAVING与WHERE切换。所以查询的DRYer版本是：

SELECT company, credit_limit, open_invoice_total, open_orders_total FROM ( SELECT arc.company, arc.credit_limit, sum(ard.unit_price * ard.invoice_qty) as open_invoice_total, sum(od.total_qty_ord * od.unit_price) as open_orders_total FROM iqms.arprepost_detail ard INNER JOIN iqms.arprepost arp ON ard.arprepost_id = arp.id INNER JOIN iqms.arcusto arc ON arp.arcusto_id = arc.id INNER JOIN iqms.ord_detail od ON o.id = od.orders_id INNER JOIN iqms.orders o ON arc.id = o.arcusto_id GROUP BY arc.company, arc.credit_limit ) AS nested WHERE (open_invoice_total + open_orders_total) > arc.credit_limit;

而且，如果您愿意，CTE可能会使其更具可读性：

;WITH nested AS ( SELECT arc.company, arc.credit_limit, sum(ard.unit_price * ard.invoice_qty) as open_invoice_total, sum(od.total_qty_ord * od.unit_price) as open_orders_total FROM iqms.arprepost_detail ard INNER JOIN iqms.arprepost arp ON ard.arprepost_id = arp.id INNER JOIN iqms.arcusto arc ON arp.arcusto_id = arc.id INNER JOIN iqms.ord_detail od ON o.id = od.orders_id INNER JOIN iqms.orders o ON arc.id = o.arcusto_id GROUP BY arc.company, arc.credit_limit ) SELECT company, credit_limit, open_invoice_total, open_orders_total FROM nested WHERE (open_invoice_total + open_orders_total) > arc.credit_limit;

SQL;求和2个字段，然后将它们一起添加

1 个答案: