Roll up and sum values of formula field

[lukva]

I want to measure workload in a week. 

TABLE 1
A) i use google calendar
B) In airtable DATETIME dif give me the duration: 02:00
C) The weeknumber is a formula week(Start) =  So i get Week 2022_5

TABLE 2 
This contains only weeknumbers: 2022_55

2 problems:
a: When i link records, I can't link with the weeknumber 2022_5 because this is a calculated field (with a formula). If fill this manually in, the link is working
b: The duration is also calculated field DateTimeDif(end-start) but I cannot use this field in a rollup field. 
If i add manually activities duration, then this work...

So, I come from filemaker and it feels a lack because i can't link records using Calculated Formulafields to link. 
Or is it wrong? 

[Ben_Young1]

Hey @lukva! 

I might be misunderstanding some of the finer details, but based on what you're describing, I would create an automation that is responsible for relating your event records (from Table 1) to the correct record in Table 2.

I would configure the automation to watch for records in Table 1 that (1) are not linked to a record in Table 2, and (2) does not have an empty value in your DATEDIFF() formula field.
From there, utilize a Find records action to search Table 2 for the correct week record. Finally, update the triggering event record and link it to the record found in the Find records action.

Let me know if you want a more in-depth look at what this might look like and I'd be happy to put something together for you to look at.

[lukva]

I try to figger out this automation, not found yet how to 'set a field with a formula' when something was triggererd. An idea is indeed if a record is created the value of the formula is set into a number field. 

But it feels strange that i can't use formala fields to link records with another database.