具有非唯一日期的SQL Sum

Question

我正在嘗試編寫一個SQL查詢，該查詢將匯總以下兩個示例表中的總產量：

Table: CaseLots
DateProduced        kgProduced
October 1, 2013     10000
October 1, 2013     10000
October 2, 2013     10000

Table: Budget
OperatingDate       BudgetHours
October 1, 2013     24
October 2, 2013     24

我想輸出如下表：

TotalProduction   TotalBudgetHours    
30000                   48

到目前為止，這是我所擁有的代碼：

SELECT 
Sum(kgProduced) AS TotalProduction, Sum(BudgetHours) AS TotalBudgetHours
FROM 
dbo.CaseLots INNER JOIN dbo.Budget ON dbo.CaseLots.DateProduced = dbo.Budget.OperatingDate
WHERE 
dbo.Budget.OperatingDate BETWEEN '2013-10-01' AND '2013-10-02'

在一天中產生多個案件的情況下，查詢似乎是預算小時的兩倍。 我得到的表如下：

Total Production     BudgetHours
30000                72

我該如何解決？

Answer 1

想想INNER JOIN在做什么。

對於CaseLot中的每一行，它會在Budget中找到具有匹配日期的任何行。

如果要刪除SQL中的聚合語句，而僅顯示內部聯接，則會看到以下結果集：

日期生產的公斤生產的經營日期預算小時

2013年10月1日10000 2013年10月1日24

2013年10月1日10000 2013年10月1日24

2013年10月2日10000 2013年10月2日24

（該死的StackOverflow，為什么你沒有Markdown的表:(）

在此基礎上運行聚合很容易看到您如何獲得72小時的結果。

正確的查詢需要首先聚合CaseLots表，然后再聯接到Budget表。

SELECT DateProduced, TotalKgProduced, SUM(BudgetHours) AS TotalBudgetHours
FROM
(
    SELECT DateProduced, SUM(kgProduced) AS TotalKgProduced
    FROM CaseLots
    GROUP BY DateProduced
) AS TotalKgProducedByDay
INNER JOIN
Budget
ON TotalKgProducedByDay.DateProduced = Budget.OperatingDate
WHERE DateProduced BETWEEN '1 Oct 2013' AND '2 Oct 2013'
GROUP BY DateProduced

Answer 2

問題在於INNER JOIN產生3行表，因為所有鍵都匹配。 因此，存在三個“ 24”，總和為72。

要解決此問題，將其分為兩個查詢可能會更容易。

SELECT Sum(kgProduced) AS TotalProduction
FROM dbo.CaseLots
WHERE dbo.CaseLots.OperatingDate BETWEEN '2013-10-01' AND '2013-10-02'

LEFT JOIN

SELECT Sum(BudgetHours) AS TotalBudgetHours
FROM dbo.Budget
WHERE dbo.Budget.OperatingDate BETWEEN '2013-10-01' AND '2013-10-02'

Answer 3

這可以通過以下方式輕松實現：

SELECT
   (SELECT SUM(kgProduced) FROM dbo.CaseLots WHERE DateProduced BETWEEN '2013-10-01' AND '2013-10-02') AS TotalProduction,
   (SELECT SUM(BudgetHours) FROM dbo.Budget WHERE OperatingDate BETWEEN '2013-10-01' AND '2013-10-02') AS TotalBudgetHours

無需加入兩個表。

Answer 4

嘗試這個：

select DateProduced,TotalProduction,TotalBudgetHours from
  (select DateProduced,sum(kgProduced) as TotalProduction 
  from CaseLots group by DateProduced) p
  join
  (select OperatingDate,sum(BudgetHours) as TotalBudgetHours 
  from Budget group by OperatingDate) b
  on (p.DateProduced=b.OperatingDate)
where p.DateProduced between '2013-10-01' AND '2013-10-02'

Answer 5

對於這種特殊情況，其他答案更為簡單。 但是，如果你需要SUM在10個不同的值CaseLots表，你需要10個不同的子查詢。 以下是一個通用的，可擴展的解決方案：

SELECT 
    SUM(DayKgProduced) AS TotalProduction, 
    SUM(BudgetHours) AS TotalBudgetHours
FROM (
    SELECT 
        DateProduced,
        SUM(kgProduced) AS DayKgProduced, 
    FROM dbo.CaseLots 
    WHERE DateProduced BETWEEN '2013-10-01' AND '2013-10-02' 
    GROUP BY DateProduced
) DailyTotals
INNER JOIN dbo.Budget b ON DailyTotals.DateProduced = b.OperatingDate

首先，你SUM生產的每一個CaseLot不必SUM的BudgetHours。 如果在上面的查詢中使用SELECT * FROM ，則會看到：

Date        DayKgProduced  BudgetHours
2013-10-01  20000          24 
2013-10-02  10000          24

但是，您需要總計，因此我們將這些每日值SUM ，正確得出：

TotalProduction  TotalBudgetHours
30000            48