Properly 'Joining' two Cross Applies - sql

Question

I've got a query with three Cross-Applies that gather data from three different tables. The first Cr-Ap assists the 2nd and 3rd Cr-Ap's. It finds the most recent ID of a certain refill for a 'cartridge', the higher the ID the more recent the refill.
The second and third Cr-Ap's gather the SUMS of items that have been refilled and items that have been dispensed under the most recent Refill.
If I run the query for Cr-Ap 2 or 3 separately the output would look something like:
ID Amount
1 100
2 1000
3 100
4 0
5 0
etc
Amount would be either the amount of dispensed or refilled items.
Only I don't want to run these queries separately, I want them next to each other.
So what I want is a table that looks like this:
ID Refill Dispense
1 100 1
2 1000 5
3 100 7
4 0 99
5 0 3
etc
My gut tells me to do
INNER JOIN crossaply2 ON crossapply3.ID = crossapply2.ID
But this doesn't work. I'm still new to SQL so I don't exactly know what I can and can't join, what I do know is that you can use crossapply as a join (sorta?). I think that might be what I need to do here, I just don't know how.
But that's not it, there's another complication, there are certain refills where nothing gets dispensed. In these scenarios the crossapply I wrote for dispenses won't return anything for that refillID. With nothing I don't mean NULL, I mean it just skips the refillID. But I'd like to see a 0 in those cases. Because it just skips over those ID's I can't get COALESCE or ISNULL to work, this might also complicate the joining of these two applies. Because an INNER JOIN would skip any line where there is no Dispensed amount, even though there is a Refilled amount Id like to see.
Here is my code:
-- Dispensed SUM and Refilled SUM combined
SELECT [CartridgeRefill].[FK_CartridgeRegistration_Id]
,Refills.Refilled
,Dispenses.Dispensed
FROM [CartridgeRefill]
CROSS APPLY(
SELECT MAX([CartridgeRefill].[Id]) AS RecentRefillID
FROM [CartridgeRefill]
GROUP BY [CartridgeRefill].[FK_CartridgeRegistration_Id]
) AS RecentRefill
CROSS APPLY(
SELECT [CartridgeRefill].[FK_CartridgeRegistration_Id] AS RefilledID
,SUM([CartridgeRefillMedication].[Amount]) AS Refilled
FROM [CartridgeRefillMedication]
INNER JOIN [CartridgeRefill] ON [CartridgeRefillMedication].[FK_CartridgeRefill_Id] = [CartridgeRefill].[Id]
WHERE [CartridgeRefillMedication].[FK_CartridgeRefill_Id] = RecentRefill.RecentRefillID
GROUP BY [CartridgeRefill].[FK_CartridgeRegistration_Id]
) AS Refills
CROSS APPLY(
SELECT [CartridgeRefill].[FK_CartridgeRegistration_Id] AS DispensedID
,SUM([CartridgeDispenseAttempt].[Amount]) AS Dispensed
FROM [CartridgeDispenseAttempt]
INNER JOIN [CartridgeRefill] ON [CartridgeDispenseAttempt].[FK_CartridgeRefill_Id] = [CartridgeRefill].[Id]
WHERE [CartridgeDispenseAttempt].[FK_CartridgeRefill_Id] = RecentRefill.RecentRefillID
GROUP BY [CartridgeRefill].[FK_CartridgeRegistration_Id]
) AS Dispenses
GO
The output of this code is as follows:
1 300 1
1 300 1
1 200 194
1 200 194
1 200 8
1 200 8
1 0 39
1 0 39
1 100 14
1 100 14
1 200 1
1 200 1
1 0 28
1 0 28
1 1000 102
1 1000 102
1 1000 557
1 1000 557
1 2000 92
1 2000 92
1 100 75
1 100 75
1 100 100
1 100 100
1 100 51
1 100 51
1 600 28
1 600 28
1 200 47
1 200 47
1 200 152
1 200 152
1 234 26
1 234 26
1 0 227
1 0 227
1 10 6
1 10 6
1 300 86
1 300 86
1 0 194
1 0 194
1 500 18
1 500 18
1 1000 51
1 1000 51
1 1000 56
1 1000 56
1 500 48
1 500 48
1 0 10
1 0 10
1 1500 111
1 1500 111
1 56 79
1 56 79
1 100 6
1 100 6
1 44 134
1 44 134
1 1000 488
1 1000 488
1 100 32
1 100 32
1 100 178
1 100 178
1 500 672
1 500 672
1 200 26
1 200 26
1 500 373
1 500 373
1 100 10
1 100 10
1 900 28
1 900 28
2 900 28
2 900 28
2 900 28
etc
It is total nonsense that I can't do much with, it goes on for about 20k lines and goes through all the ID's, eventually.
Any help is more than appreciated :)

Answer 1

Looks like overcomplicated a bit.
Try
WITH cr AS (
SELECT [FK_CartridgeRegistration_Id]
,MAX([CartridgeRefill].[Id]) RecentRefillID
FROM [CartridgeRefill]
GROUP BY [FK_CartridgeRegistration_Id]
)
SELECT cr.[FK_CartridgeRegistration_Id], Refills.Refilled, Dispenses.Dispensed
FROM cr
CROSS APPLY(
SELECT SUM(crm.[Amount]) AS Refilled
FROM [CartridgeRefillMedication] crm
WHERE crm.[FK_CartridgeRefill_Id] = cr.RecentRefillID
) AS Refills
CROSS APPLY(
SELECT SUM(cda.[Amount]) AS Dispensed
FROM [CartridgeDispenseAttempt] cda
WHERE cda.[FK_CartridgeRefill_Id] = cr.RecentRefillID
) AS Dispenses;