选择所有列值作为总计并乘以

Question

这是我的数据库结构：

发票

• ID

• 公司

发票行

• LineID

• 数量

• 价格

这些是我的行：

Invoice
ID  Company
1   XYZ
2   ZYX

InvoiceLine
LineID  InvoiceID   quantity    price
1       1           1           10
2       1           5           10

3       2           1           20

我要生成的是动态选择总发票价格：

理想结果

1 XYZ 60
2 ZYX 20

我为此使用以下查询：

select ID, cil.quantity * cil.unitPrice as invoiceTotal from Invoice ci
join InvoiceLine as cil on ci.invoiceID = cil.invoiceID 

问题是此查询为第一张发票返回2行。

这是为什么？如何选择发票行的所有值？

Answer 1

您要group by：

select ci.id, sum(cil.quantity * cil.unitPrice) as invoiceTotal
from Invoice ci join
     InvoiceLine cil
     on ci.invoiceID = cil.invoiceID 
group by ci.id;

但是，您甚至不需要join：

select cil.id, sum(cil.quantity * cil.unitPrice) as invoiceTotal
from InvoiceLine cil
group by cil.id;

Answer 2

    select Invoice.id,Invoice.Company sum(InvoiceLine.quantity * InvoiceLine.unitPrice) as TotalSum
    from Invoice join
         InvoiceLine cil
         on Invoice.invoiceID = InvoiceLine.invoiceID 
    group by Invoice.id,Invoice.Company

order by Invoice.Company ;