Sumowanie wartości dwóch tablic, nawet jeśli w drugiej tablicy nie ma konkretnej wartości

Witam,
Tablica 1 Activities - zawiera ID, i id dane klienta
Tablica 2 Faktury - Zawiera Activities.ID i 2 kolumny (Faktura i Inredning)

W wyniku chce otrzymac wszystkie wiersze z Activities (wszystkich klientow)

• oraz zsumowanie wartosci z Tablicy Faktury (dla kolumny Faktura i Inredning)

Moje zapytanie dobrze sumuje, jednak jesli w tablicy Faktury nie bedzie zadnej pozycji dla danego ID To w wyniku nie dostane wszystkich pozycji z Activities. (tylko te które mają jakąś fakure)

1. będę wdzięczny jak dostanę kod który to wykona.
2. Jeszcze bardziej będę wdzięczny jak moj kod będzie zmodyfikowany a nie nowy kod który będzie miał zupełnie inna składnię której nie zrozumie i się nie nie nauczę.

SELECT Activities.id, Activities.date_from, Activities.zz_customer_name, Activities.zz_address, Activities.zz_project_number, Activities.Econ_Fakturerad_total as At_fakturera_renovering, 
Sum(case when Faktury.Vad = "Faktura" then Faktury.Belopp else 0 end) as REDO_Faktura, 
Activities.Econ_Fakturerad_total - Sum(case when Faktury.Vad = "Faktura" then Faktury.Belopp else 0 end) As Saknas_renovering,

Case
When invoice_ready = 0 THEN "None"
When invoice_ready = 1 THEN "Avslutat"
When invoice_ready = 2 THEN "fakturerad"
When invoice_ready = 3 THEN "Special"
When invoice_ready = 4 THEN "Klart"
When invoice_ready = 5 THEN "Klart Special"
End AS Status,


Activities.Econ_Inredning1 as Att_fakturera_Inredning,
Sum(case when Faktury.Vad = "inredning" then Faktury.Belopp else 0 end) as REDO_Inredning,
Activities.Econ_Inredning1 - Sum(case when Faktury.Vad = "inredning" then Faktury.Belopp else 0 end) As Saknas_faktura

FROM `Activities` , `Faktury`
where Activities.date_from > "2023-11-05" And Activities.date_from < "2023-12-15"   and Activities.zz_project_type = 1 and Activities.zz_customer_name <> ""  And Faktury.Activity_ID = Activities.Id
Group BY Activities.id  
ORDER BY `id` ASC

https://dotnettutorials.net/lesson/left-outer-join-mysql/#:~:text=What%20is%20Left%20Outer%20Join%20in%20MySQL%3F,the%20left%20join%20in%20MySQL.

SELECT 
	Activities.id
	, Activities.date_from
	, Activities.zz_customer_name
	, Activities.zz_address
	, Activities.zz_project_number
	, Activities.Econ_Fakturerad_total as At_fakturera_renovering
	, REDO_Faktura
	, Activities.Econ_Fakturerad_total - REDO_Faktura As Saknas_renovering
	, Case
		When invoice_ready = 0 THEN "None"
		When invoice_ready = 1 THEN "Avslutat"
		When invoice_ready = 2 THEN "fakturerad"
		When invoice_ready = 3 THEN "Special"
		When invoice_ready = 4 THEN "Klart"
		When invoice_ready = 5 THEN "Klart Special"
		End AS Status
	, Activities.Econ_Inredning1 as Att_fakturera_Inredning
	, REDO_Inredning
	, Activities.Econ_Inredning1 - REDO_Inredning As Saknas_faktura
FROM 
	`Activities` 
	LEFT JOIN (SELECT`
					Activity_ID
					,Sum(case when Faktury.Vad = "Faktura" then Faktury.Belopp else 0 end) as REDO_Faktura
					,Sum(case when Faktury.Vad = "inredning" then Faktury.Belopp else 0 end) as REDO_Inredning
				FROM
					Faktury`
				GROUP BY
				    Activity_ID) as FatkturySum  on FakturySum.Activity_ID = Activities.Id
where 
	Activities.date_from > "2023-11-05" 
	And Activities.date_from < "2023-12-15"   
	and Activities.zz_project_type = 1 
	and Activities.zz_customer_name <> ""   
ORDER BY 
	Activities.id ASC