No possible solution has been found by Rdb optimizer

  Explanation:   No  possible  solution  has  been  found  by  Rdb
  optimizer  for  the  following  reason:  - Full outer join query
  with cross strategy is not possible.  Only MATCH join  execution
  is allowed for full outer join.

  User Action:  Check if the join keys of the join predicates  are
  compatible in data type.  If the keys are not compatible, please
  apply a CAST function to make it compatible data type to be used
  as a join key in a match join strategy.