JOIN，GROUP BY和SUM單查詢

Question

發票表

invoice_id invoice_date 
------------ -------------- 
    1   2013-11-27 
    2   2013-10-09 
    3   2013-09-12 

訂單表

order_id invoice_id product  quantity total 
--------- ---------- --------- --------- ------- 
    1   1  Product 1  100  1000 
    2   1  Product 2  50  200 
    3   2  Product 1  40  400 
    4   3  Product 2  50  200 

，我想一個簡單的SQL查詢產生以下結果

products Month 9 Total Month 10 Total Mont 11 Total 
-------- ------------- -------------- ------------- 
Product 1   0    400    100  
Product 2  200    0    200 

我有試過以下sql查詢

SELECT orders.products, DATEPART(Year, invoices.invoice_date) Year, DATEPART(Month, invoices.invoice_date) Month, SUM(orders.total) [Total], 
FROM invoices INNER JOIN orders ON invoices.invoice_id=orders.invoice_id 
GROUP BY orders.products, DATEPART(Year, invoices.invoice_date), DATEPART(Month, invoices.invoice_date) 

但它什麼也沒有返回。是否有可能得到這個結果與單個查詢，我該怎麼做？由於

Answer 1

我想你想使用這裏PIVOT ...

試試這個：

WITH tmp 
AS 
(
SELECT orders.products, 
     DATEPART(Year, invoices.invoice_date) Year, 
     DATEPART(Month, invoices.invoice_date) Month, 
     SUM(orders.total) [Total] 
FROM invoices INNER JOIN orders ON invoices.invoice_id = orders.invoice_id 
GROUP BY 
     orders.products, 
     DATEPART(Year, invoices.invoice_date), 
     DATEPART(Month, invoices.invoice_date) 
) 
SELECT products, 
     ISNULL([9],0) AS Nine, ISNULL([10],0) AS Ten, ISNULL([11],0) as Eleven 
FROM tmp 
PIVOT 
(
    SUM([Total]) 
    FOR Month IN 
    ([9], [10], [11]) 
) as PVT; 

你可以在這裏編輯：http://sqlfiddle.com/#!6/6f80f/6

Answer 2

一種方式來做到這一點是案件：

Select 
    O.product, 
    Sum(Case 
     When DATEPART(M, I.invoice_Date) = 9 Then O.total 
     Else 0 
    End) as Month9, 
    Sum(Case 
     When DATEPART(M, I.invoice_Date) = 10 Then O.total 
     Else 0 
    End) as Month10, 
    Sum(Case 
     When DATEPART(M, I.invoice_Date) = 11 Then O.total 
     Else 0 
    End) as Month11 
From Invoice I 
    Left join Orders O on I.invoice_id = O.invoice_id 
Group by O.product 

有使用支點另一種方式（根據您的SQL版本）。

Select product, [9], [10], [11] 
From 
(
    Select O.Product, O.total, DatePart(M, I.Invoice_Date) as [MonthNum] 
    From Invoice I 
     Left join Orders O on I.invoice_id = O.invoice_id 
) P 
PIVOT 
(
    Sum(P.total) 
    For [MonthNum] in ([9], [10], [11]) 
) as O 

Answer 3

您最好使用這個樞軸。請記住，您必須在pivot..for..in子句中明確列出每個月。

select 
    * 
into #invoices 
from (
    select 1 as invoice_id, '2013-11-27' as invoice_date union all 
    select 2,'2013-10-09' union all 
    select 3,'2013-09-12' 
) x 


select 
    * 
into #orders 
from (
    select 1 as order_id,1 as invoice_id,'Product 1' as product,100 as quantity,1000 as total union all 
    select 2,1,'Product 2',50,200 union all 
    select 3,2,'Product 1',40,400 union all 
    select 4,3,'Product 2',50,200 
) x 

GO 


select 
    Product, 
    [9], [10], [11] 
from (
    select 
     o.product, datepart([month],i.invoice_date) as mon, 
     o.total 
    from #invoices i 
    join #orders o 
     on i.invoice_id=o.invoice_id 
) x 
pivot (
    sum(total) for mon in ([9],[10],[11]) 
) p