Fix for Oracle12c - ORA-01792: maximum number of columns in a table or view is 1000

SYMPTOMS

It is possible to get an ORA-01792 "MAXIMUM NUMBER OF COLUMNS IN A TABLE OR VIEW IS 1000"  error even when the original query does not select that many columns  in Oracle 12.1.0.2.0 version.

SOLUTION

According to the My Oracle Support, ORA-01792 is caused due to an unpublished bug.
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 hidden parameter "_fix_control"

The workaround is to set "_fix_control"='17376322:OFF'

On Session level
SQL> alter session set "_fix_control"='17376322:OFF';

OR at system level :

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

OR

Apply Patch 19509982 if available for your DBVersion and Platform

To download the patch, please follow the steps below:
1) Go To MOS
2) Click on Patches & Updates
3) In the Patch Search Section, enter your patch number <19509982> in the Patch Name or Number field.
4) Click Search
5) Click the patch that meets your DbVersion and platform
6) Read any applicable notes before downloading, then click the download button.