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具有非唯一日期的SQL Sum

[英]SQL Sum with non unique date

我正在尝试编写一个SQL查询,该查询将汇总以下两个示例表中的总产量:

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

我想输出如下表:

TotalProduction   TotalBudgetHours    
30000                   48

到目前为止,这是我所拥有的代码:

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'

在一天中产生多个案件的情况下,查询似乎是预算小时的两倍。 我得到的表如下:

Total Production     BudgetHours
30000                72

我该如何解决?

想想INNER JOIN在做什么。

对于CaseLot中的每一行,它会在Budget中找到具有匹配日期的任何行。

如果要删除SQL中的聚合语句,而仅显示内部联接,则会看到以下结果集:

日期生产的公斤生产的经营日期预算小时

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

(该死的StackOverflow,为什么你没有Markdown的表:()

在此基础上运行聚合很容易看到您如何获得72小时的结果。

正确的查询需要首先聚合CaseLots表,然后再联接到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

问题在于INNER JOIN产生3行表,因为所有键都匹配。 因此,存在三个“ 24”,总和为72。

要解决此问题,将其分为两个查询可能会更容易。

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'

这可以通过以下方式轻松实现:

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

无需加入两个表。

尝试这个:

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'

对于这种特殊情况,其他答案更为简单。 但是,如果你需要SUM在10个不同的值CaseLots表,你需要10个不同的子查询。 以下是一个通用的,可扩展的解决方案:

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生产的每一个CaseLot不必SUM的BudgetHours。 如果在上面的查询中使用SELECT * FROM ,则会看到:

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

但是,您需要总计,因此我们将这些每日值SUM ,正确得出:

TotalProduction  TotalBudgetHours
30000            48 

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