@hugues​ Can you expand on what the problem is and what you need to accomplish? Are you encountering an error?

I have a table. This table have field (FWD_id) that it's can be null. I make a featurejoiner with a other table with the same field (FWD_id), and on the second table is can be null to. I make the join on the field FWD_id. I need to validate that the record on the first table with FWD_id not null value can be link with the second table on the field FWD_id. Thank you.

@hugues​ You can use a TestFilter to test for <null> or NOT <null> - this will filter out the records that have a <null> FWD_id. You can then use the FeatureJoiner to join the two records using FWD_id. If there is no match, then you'll see those in the UnmatchedLeft and UnmatchedRight ports.