SQL Sum with non unique date - sql

Question

I'm trying to write a SQL query that will sum total production from the following two example tables:
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
I would like to output a table as follows:
TotalProduction TotalBudgetHours
30000 48
Here is what I have for code so far:
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'
It seems that the query is double summing the budget hour in instances where more than one case lot is produced in a day. The table I'm getting is as follows:
Total Production BudgetHours
30000 72
How do I fix this?

Answer 1

Think about what the INNER JOIN is doing.
For every row in CaseLot, its finding any row in Budget that has a matching date.
If you were to remove your aggregation statements in SQL, and just show the inner join, you would see the following result set:
DateProduced kgProduced OperatingDate BudgetHours
October 1, 2013 10000 October 1, 2013 24
October 1, 2013 10000 October 1, 2013 24
October 2, 2013 10000 October 2, 2013 24
(dammit StackOverflow, why don't you have Markdown for tables :( )
Running your aggregation on top of that it is easy to see how you get the 72 hours in your result.
The correct query needs to aggregate the CaseLots table first, then join onto the Budget table.
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

The problem is in the INNER JOIN produces a 3 row table since the keys match on all. So there is three '24's with a sum of 72.
To fix this, it would probably be easier to split this into two queries.
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

This could be easily achieved by this:
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
There's no need for joining the two tables.

Answer 4

The other answers are simpler for this particular case. However if you needed to SUM 10 different values on the CaseLots table, you'd need 10 different subqueries. The following is a general, more scaleable solution:
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
First you SUM the production of each CaseLot without having to SUM the BudgetHours. If you used a SELECT * FROM in the query above you'd see:
Date DayKgProduced BudgetHours
2013-10-01 20000 24
2013-10-02 10000 24
But you want the overall total, so we SUM those daily values, correctly producing:
TotalProduction TotalBudgetHours
30000 48

Answer 5

Try this:
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'