Counting all records from inner-join - sql

Question

I have 4 tables that has aantal ( count ) and each tables shows normal numbers or numbers with - before (example: -20) now I need to count all that records. but I don't know how I can fix that.
Sorry I am a noob in sql.
this is my code
The problem that i facing to is tha all records from the different tables that has column aantal not counting in total.
example:
CSSDKMagento_10_Plankvoorraad returns 10
CSSDKMagento_20_GeenAllocatieWelFiat returns -3 and -2
CSSDKMagento_30_AllocatieVoorraad returns 5
CSSDKMagento_50_AllocatieBestellingBinnen returns -1 and -1
That means that i get on return from Voorraad is 8.
I tried count(*) but that is not the solution. with best way I can do it?
SELECT
i.ItemCode,
g.warehouse,
SUM(g.aantal) AS Voorraad,
MAX(CASE
WHEN g.transtype = 'N' THEN g.sysmodified
ELSE NULL
END) AS LastDate
FROM dbo.CSSDKMagento_10_Plankvoorraad AS g
INNER JOIN dbo.Items AS i
ON (g.artcode = i.ItemCode)
INNER JOIN dbo.CSSDKMagento_20_GeenAllocatieWelFiat AS a
ON (a.artcode = i.ItemCode)
INNER JOIN dbo.CSSDKMagento_30_AllocatieVoorraad AS v
ON (v.artcode = i.ItemCode)
INNER JOIN dbo.CSSDKMagento_50_AllocatieBestellingBinnen AS b
ON (b.artcode = i.ItemCode)
WHERE
i.itemcode = 'TEST'
GROUP BY i.itemcode,
g.warehouse;

Answer 1

Try this
SELECT
i.ItemCode,
g.warehouse,
SUM(g.aantal)+SUM(a.aantal)+SUM(v.aantal)+SUM(b.aantal) AS Voorraad,
MAX(CASE
WHEN g.transtype = 'N' THEN g.sysmodified
ELSE NULL
END) AS LastDate
FROM dbo.CSSDKMagento_10_Plankvoorraad AS g
INNER JOIN dbo.Items AS i
ON (g.artcode = i.ItemCode)
INNER JOIN dbo.CSSDKMagento_20_GeenAllocatieWelFiat AS a
ON (a.artcode = i.ItemCode)
INNER JOIN dbo.CSSDKMagento_30_AllocatieVoorraad AS v
ON (v.artcode = i.ItemCode)
INNER JOIN dbo.CSSDKMagento_50_AllocatieBestellingBinnen AS b
ON (b.artcode = i.ItemCode)
WHERE
i.itemcode = 'TEST'
GROUP BY i.itemcode,
g.warehouse;

Answer 2

Edited:
SELECT SUM(Voorraad) FROM (
SELECT
i.ItemCode,
g.warehouse,
g.aantal AS Voorraad,
MAX(CASE
WHEN g.transtype = 'N' THEN g.sysmodified
ELSE NULL
END) AS LastDate
FROM dbo.CSSDKMagento_10_Plankvoorraad AS g
INNER JOIN dbo.Items AS i
ON (g.artcode = i.ItemCode)
INNER JOIN dbo.CSSDKMagento_20_GeenAllocatieWelFiat AS a
ON (a.artcode = i.ItemCode)
INNER JOIN dbo.CSSDKMagento_30_AllocatieVoorraad AS v
ON (v.artcode = i.ItemCode)
INNER JOIN dbo.CSSDKMagento_50_AllocatieBestellingBinnen AS b
ON (b.artcode = i.ItemCode)
WHERE
i.itemcode = 'TEST' enter code here
GROUP BY i.itemcode,
g.warehouse
)src

Answer 3

Looks like following would work:
WITH itemCodesScope AS
(
SELECT 'TEST' as target_ItemCode
),
aggregated_CSSDKMagento_10_Plankvoorraad AS
(
SELECT g.artcode,
g.warehouse,
COUNT(g.aantal) as count_aantal,
SUM(g.aantal) as sum_aantal,
MAX(CASE
WHEN g.transtype = 'N' THEN g.sysmodified
ELSE NULL
END) AS LastDate
FROM dbo.CSSDKMagento_10_Plankvoorraad AS g
JOIN itemCodesScope ON itemCodesScope.target_itemCode = g.artcode
GROUP BY
g.artcode,
g.warehouse
),
aggregated_CSSDKMagento_20_GeenAllocatieWelFiat AS
(
SELECT a.artcode ,
COUNT(a.aantal) as count_aantal,
SUM(a.aantal) as sum_aantal
FROM dbo.CSSDKMagento_20_GeenAllocatieWelFiat AS a
JOIN itemCodesScope ON itemCodesScope.target_itemCode = a.artcode
GROUP BY
a.artcode
),
aggregated_CSSDKMagento_30_AllocatieVoorraad AS
(
SELECT v.artcode ,
COUNT(v.aantal) as count_aantal,
SUM(v.aantal) as sum_aantal
FROM dbo.CSSDKMagento_30_AllocatieVoorraad AS v
JOIN itemCodesScope ON itemCodesScope.target_itemCode = v.artcode
GROUP BY
v.artcode
),
aggregated_CSSDKMagento_50_AllocatieBestellingBinnen AS
(
SELECT b.artcode ,
COUNT(b.aantal) as count_aantal,
SUM(b.aantal) as sum_aantal
FROM dbo.CSSDKMagento_50_AllocatieBestellingBinnen AS b
JOIN itemCodesScope ON itemCodesScope.target_itemCode = b.artcode
GROUP BY
b.artcode
)
SELECT
g.artcode as ItemCode,
g.warehouse,
g.sum_aantal AS Voorraad,
g.LastDate AS LastDate,
g.sum_aantal + ISNULL(a.sum_aantal, 0) + ISNULL(v.sum_aantal, 0) + ISNULL(b.sum_aantal, 0) as sum_aantal,
g.count_aantal + ISNULL(a.count_aantal, 0) + ISNULL(v.count_aantal, 0) + ISNULL(b.count_aantal, 0) as count_aantal
FROM aggregated_CSSDKMagento_10_Plankvoorraad AS g
INNER JOIN dbo.Items AS i
ON (g.artcode = i.ItemCode)
INNER JOIN itemCodesScope
ON itemCodesScope.target_itemCode = i.ItemCode
LEFT JOIN aggregated_CSSDKMagento_20_GeenAllocatieWelFiat AS a
ON (a.artcode = i.ItemCode)
LEFT JOIN aggregated_CSSDKMagento_30_AllocatieVoorraad AS v
ON (v.artcode = i.ItemCode)
LEFT JOIN aggregated_CSSDKMagento_50_AllocatieBestellingBinnen AS b
ON (b.artcode = i.ItemCode)
Explanation
SQL-joins produce Cartesian Products, which most probably led to unexpected results in the initial query. Here there are 4 'amount'-tables which are connected via Joins with conditions 'ON (b.artcode = i.ItemCode)', so if there any table contains several records per condition output will contain several records per ItemCode.
Let's say there are 9 records in a-table with a.artcode per single i.ItemCode, so there is a one-to-many relation. And let's say there is 1 record in b-table per single i.ItemCode. Output of Join will have 9 a.aantal records, but 9 repeated b.aantal records as well. Given that there is an aggregation (group by) it will effect that SUM(b.aantal) in this Joins-query will produce 9-time more than sum(b.aantal) in standalone query on b-table only.
Cartesian Product could be seen more easily, if run the initial query without aggregation:
SELECT *
FROM dbo.CSSDKMagento_10_Plankvoorraad AS g
INNER JOIN dbo.Items AS i
ON (g.artcode = i.ItemCode)
INNER JOIN dbo.CSSDKMagento_20_GeenAllocatieWelFiat AS a
ON (a.artcode = i.ItemCode)
INNER JOIN dbo.CSSDKMagento_30_AllocatieVoorraad AS v
ON (v.artcode = i.ItemCode)
INNER JOIN dbo.CSSDKMagento_50_AllocatieBestellingBinnen AS b
ON (b.artcode = i.ItemCode)
WHERE
i.itemcode = 'TEST'
The fixture was: doing group by aggregation before making joins. Most convenient way for this imho is CTE. With CTE I created 4 temporary tables with aggregates per ItemCode, so temporary tables are one-to-one per ItemCode. Then Joins on one-to-one produce just single output row per ItemCode.