Difference between Start and End Dates in Months as per Year

[qlikwiz123]

I need to show difference between Start Date and DATE in Months in such a way that the number of months divide as per the year.

For example,  for ID 1, 

ID, Year, Months

1, 2020, 1

1, 2021, 12

.....

QVW is attached. Any lead is appreciated 

[Anil_Babu_Samineni]

One way is

Load ID, [Start Date], [Start Date] as DateField From T1;

Join

Load ID, [DATE], [DATE] as DateField From T1;

Create Chart like'

Dimension : ID

Dimension : Year(DateField )

Measure : Num(Month([Start Date])-Month(DATE))