I want to match up tuples from 2 relations. For each key, the 2 relations
will always have the same number of tuples and match by position (the first
tuple in each are a match, the second tuple in each, etc).
so if I have
relation1 = 5,9,7
relation2 = z,a,d
I want to end up with
relation3 = (5,z),(9,a),(7,d)
I figure I need a way to generate a matching key on the ordered tuples of
the relations and then do a cogroup. But I'm stuck on generating the key.
Since adding a field is a project, I assume this has to be done as part of
a foreach loop. But I'm not sure how I can maintain the order while adding
a field to each tuple.