Hi Raj,
Initially u need to pull then in a loop then u can compare fields. under the loop u can mention a branch and sequence condition . Or you can use some of the java utilities of string compare.
flow is here
loop on first document
loop on second document
branch on ( with no condition & evaluate labels true)
sequence : doc1/sourcename == doc2/sourcename
sequence : doc1/fieldname == doc2/fieldname
Loop over doc1\list1
–loop over doc2\list2
— branch (evaluate lable set to true)
----(%doc1\list1\source%==%doc2\list2\source% && %doc1\list1\value%==%doc2\list2\value%):sequence