text: -- selectB.test
  -- 
  -- execsql {
  --       SELECT * FROM (SELECT e FROM t2 UNION ALL SELECT f FROM t2)
  --       EXCEPT 
  --       SELECT c FROM t1
  --       ORDER BY c DESC
  -- }
  SELECT * FROM (SELECT e FROM t2 UNION ALL SELECT f FROM t2)
  EXCEPT 
  SELECT c FROM t1
  ORDER BY c DESC