We are experiencing the Oracle12c - ORA-01792: maximum number of columns in a table or view is 1000 after an upgrade from 11g to 12c which involves a MINUS query. The individual queries execute without the error.
In other words lets say the query is SELECT A, B FROM HN1 MINUS SELECT A, B FROM HN2
The statement SELECT A, B FROM HN1 executes without error. Likewise SELECT A, B FROM HN2.
However when they are combine the above error shows. There are about 18 columns in the query and when Oracle does internal query processing creating inline temporary tables it may strike the 1000 limit. At the moment I will not reduce the amount of columns in the query. Is there an Oracle hint I can use to make it function or any other strategy.