How to fix the Oracle error ORA-12013: updatable materialized views must be simple enough to do fast refresh?

In this post, you’ll learn more about the Oracle ErrorORA-12013: updatable materialized views must be simple enough to do fast refresh with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

ORA-12013: updatable materialized views must be simple enough to do fast refresh

Reason for the Error ORA-12013: updatable materialized views must be simple enough to do fast refresh

The updatable materialized view query contained a join, subquery, union, connect by, order by, or group by caluse.

How to fix the Error ORA-12013: updatable materialized views must be simple enough to do fast refresh ?

You can fix this error in Oracle by following the below steps

Make the materialized view simpler. If a join is really needed, make multiple simple materialized views then put a view on top of them.