Oracle Error QSM-02175: some query block in UNION ALL MV is not fast refreshable

Oracle Error Message

QSM-02175: some query block in UNION ALL MV is not fast refreshable

Reason for the Error

For a materialized view with UNION ALL to be fast refreshable, each query block must conform to a fast refreshable materialized join view or materialized aggregate view.

Solution

Check each query block in the UNION ALL to ensure it is either a materialized view with joins or aggregates.