sharepoint online – difference between dates for two last articles of the same order

I tried to search the forum and Google for the answer, but to no avail.

I have a list:

we say:

"Site ID", "Date of Request"
11111, 2019-03-05
11110, 2019-03-15
11111, 2019-05-01

I want to create a column "weeks since the last request" for the same "site iD".

Location ID, Requested Date, Weeks Since Last Request
11111, 2019-03-05, 0
11110, 2019-03-15, 0
11111, 2019-05-01,8 (rounded)

Best if it can even be filled with additional metadata, eg.

Location ID, Requested Date, Weeks Since Last Request, Type
11110, 2019-03-05, 0, PSV
11111, 2019-03-05, 0, PSV
11110, 2019-03-15, 0, MV
11111, 2019-05-01, 8, PSV

However, if the difference between 11110 PSV and MV is 0 because they are of a different type, the difference between 11111 is calculated because they are of the same type.

I'm grateful for any help you need.

Yours sincerely,
Vladimir