How to fix the Oracle error QSM-02123: subquery and UNION mv’s must be primary key mv’s?

In this post, you’ll learn more about the Oracle ErrorQSM-02123: subquery and UNION mv’s must be primary key mv’s with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

QSM-02123: subquery and UNION mv’s must be primary key mv’s

Reason for the Error QSM-02123: subquery and UNION mv’s must be primary key mv’s

The capability in question is not supported when the materialized view is not a primary key materialized view and uses subqueries or the union operator in this context.

How to fix the Error QSM-02123: subquery and UNION mv’s must be primary key mv’s ?

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

Re-create the materialized view as a primary key materialized view.