Oracle suggest to alter the query and/or view definitions to avoid the error. However in cases where the SQL cannot be adjusted then the checking can be disabled by:  

SQL> alter system set "_fix_control"='17376322:OFF';

Alternatively an interim patch for this fix (patch 19509982) can be applied to disable the error by default.

For details:
Bug 19509982 Disable raising of ORA-1792 by default
Select Statement Throws ORA-01792 Error

http://dba.stackexchange.com/questions/128621/understanding-ora-01792-maximum-number-of-columns-in-a-table-or-view-is-1000