SQL joins not giving me correct totals - sql

Question

I'm trying to get a report for figures from multiple transaction tables. Each table has a foreign key that is a lookup for the day it was taken on, and what location it was taken at called Site_Lookup_Id. It's giving me figures that are much larger than they should be.
#Site_Lookup_Ids dbo.Id_List READONLY
SELECT SL.Site_Lookup_Id, D.[Start],SUM(I.Amount) AS Income,
SUM(P.Amount) AS Payouts,SUM(DP.Amount) AS Deposit
FROM CashUp_Site_Lookup SL
INNER JOIN #Site_Lookup_Ids IDs ON Ids.Id = SL.Site_Lookup_Id
INNER JOIN CashUp_Day D ON SL.Day_Id = D.Day_Id
LEFT JOIN CashUp_Deposit DP ON DP.Redeemed_Site_Lookup_Id = SL.Site_Lookup_Id
AND DP.No_Show != 1
LEFT JOIN CashUp_Income I ON I.Site_Lookup_Id = SL.Site_Lookup_Id
LEFT JOIN CashUp_Payout P ON P.Site_Lookup_Id = SL.Site_Lookup_Id
GROUP BY SL.Site_Lookup_Id, D.[Start]
Not all sums will have a value as some days no transactions for a given table will be taken on the day - In this the value should be zero.
The issue is that running this gives me crazy high values - £7500 for income against one day, when if I do a simple check it's £40 for that day like so.
SELECT SUM(Amount) FROM Cashup_Income WHERE Site_Lookup_Id IN (values...)

Answer 1

Maybe something like...
It really depends on the relationships and when you want the values to be summed.
SELECT SL.Site_Lookup_Id
, D.[Start]
, SUM(I.Amount) over (partition by Key of I table) AS Income
, SUM(P.Amount) over (partition by Key of P table) AS Payouts
, SUM(DP.Amount) over (partition by Key of DP Table) AS Deposit
FROM CashUp_Site_Lookup SL
INNER JOIN #Site_Lookup_Ids IDs ON Ids.Id = SL.Site_Lookup_Id
INNER JOIN CashUp_Day D ON SL.Day_Id = D.Day_Id
LEFT JOIN CashUp_Deposit DP ON DP.Redeemed_Site_Lookup_Id = SL.Site_Lookup_Id
AND DP.No_Show != 1
LEFT JOIN CashUp_Income I ON I.Site_Lookup_Id = SL.Site_Lookup_Id
LEFT JOIN CashUp_Payout P ON P.Site_Lookup_Id = SL.Site_Lookup_Id
GROUP BY SL.Site_Lookup_Id, D.[Start]
The problem stems from the fact that your tables are 1:M Causing values to repeat. These repeated values are then getting added to your sum. The joins cause this issue. So I think you can sum using a partition to eliminate the duplicates or:
Use derived tables or a CTE and sum the values BEFORE you join.
Using CTE's (Common Table Expressions)
WITH DP AS (SELECT sum(Amount) As Deposit
, Redeemed_Site_Lookup_ID
FROM CashUp_Deposit
WHERE No_Show !=1
GROUP BY Redeemed_Site_Lookup_ID),
I AS (SELECT sum(Amount) as Income
, Site_Lookup_Id
FROM CashUp_Income
GROUP BY Site_Lookup_Id),
P AS (SELECT sum(Amount) as Payouts
, Site_Lookup_Id
FROM CashUp_Payout
GROUP BY Site_Lookup_Id)
SELECT SL.Site_Lookup_Id
, D.[Start]
, Income
, Payouts
, Deposit
FROM CashUp_Site_Lookup SL
INNER JOIN #Site_Lookup_Ids IDs
ON Ids.Id = SL.Site_Lookup_Id
INNER JOIN CashUp_Day D
ON SL.Day_Id = D.Day_Id
LEFT JOIN DP
ON DP.Redeemed_Site_Lookup_Id = SL.Site_Lookup_Id
LEFT JOIN I
ON I.Site_Lookup_Id = SL.Site_Lookup_Id
LEFT JOIN P
ON P.Site_Lookup_Id = SL.Site_Lookup_Id

Answer 2

Presumably, you are generating a Cartesian product with your joins. Because you have no filtering, do the aggregation before the joins:
LEFT JOIN
(SELECT DP.Redeemed_Site_Lookup_Id, SUM(DP.Amount) AS Deposit
FROM CashUp_Deposit DP
WHERE DP.No_Show != 1
GROUP BY DP.Redeemed_Site_Lookup_Id
) DP
ON DP.Redeemed_Site_Lookup_Id = SL.Site_Lookup_Id LEFT JOIN
(SELECT I.Site_Lookup_Id, SUM(I.Amount) AS Income
FROM CashUp_Income I
GROUP BY I.Site_Lookup_Id
) I
ON I.Site_Lookup_Id = SL.Site_Lookup_Id LEFT JOIN
(SELECT P.Site_Lookup_Id, SUM(P.Amount) AS Payout
FROM CashUp_Payout P
GROUP BY I.Site_Lookup_Id
) P
ON P.Site_Lookup_Id = SL.Site_Lookup_Id
Then adjust the rest of your query to remove the GROUP BY and SUM()s.