DataStage

Stuck with the problem that DataStage complains about column names not being found? And you are really extra sure that the query does return records. Mentioned message can mean that DS cannot determine the data structure it is supposed to process because the query does not return anything. Fine so far, but it also gets thrown in other occasions and at the wrong place as can be seen in the screenshots attached. The problem there is not the hash key builder but the query of the reader. We read a null value without anything to it. So, DS cannot tell what type the column being returned is. If you cast explicitely to a type, you are fine again: select cast(null as char(1)) from dual; Don't get fooled. One single column of undefined type suffices to make DS throw this error. I stumbled over this in need for a quick and dirty solution, but I reckon, that if you are in need of returning nulls explicitely to add a column, you would better work your design over.