issue while joining a calculation view in a composite provider

I am trying to join a calculation view which has 4 fields(sample data)

Claim Reserve Benefit Category

1) 100, EP, <null>, X

2) 100, <null>, FP,Y

I would like to add the category to the composite provider and when I try to do a join with the join condition on claim, reserve and benefit, I am getting blank values in category as output. is there any possibility to make this work.

thanks!