Postgres 9.3 copy data from another table with relation
I think something like this would work -- let me know if it doesn't

WITH forms_data AS (
  SELECT id, calldatetime FROM forms
) UPDATE qa_forms qf
  SET calldatetime = fd.calldatetime
  FROM forms_data fd
  WHERE qf.id = fd.id;


Edit (better version, suggested by dezso):

UPDATE qa_forms qf
SET calldatetime = f.calldatetime
FROM forms f
WHERE qf.id = f.id;