How to fix the Oracle error QSM-02174: the materialized view does not have a UNION ALL marker column?

In this post, you’ll learn more about the Oracle ErrorQSM-02174: the materialized view does not have a UNION ALL marker column with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

QSM-02174: the materialized view does not have a UNION ALL marker column

Reason for the Error QSM-02174: the materialized view does not have a UNION ALL marker column

For a materialized view with UNION ALL to be fast refreshable, it must have a UNION ALL marker column. This is a constant column, at the same ordinal position in each query block and must have distinct values in each query block.

How to fix the Error QSM-02174: the materialized view does not have a UNION ALL marker column ?

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

Add a UNION ALL marker column to each query block in the UNION ALL query defining the materialized view.