framework/resources/Functional/joins/nulleqjoin/mixedcomprtr.q

SELECT * 
FROM tbl_bigint_l t1, tbl_bigint_r t2 
WHERE  t1.col_int = t2.col_int 
AND (
      (t1.col_bigint=t2.col_bigint) 
      OR 
      (t1.col_bigint IS NULL AND t2.col_bigint IS NULL)
);