How to fix the Oracle error QSM-02150: select lists must be identical across the UNION operator?

In this post, you’ll learn more about the Oracle ErrorQSM-02150: select lists must be identical across the UNION operator with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

QSM-02150: select lists must be identical across the UNION operator

Reason for the Error QSM-02150: select lists must be identical across the UNION operator

You have specified a materialized view using the UNION operator and the respective queries on each side of the UNION operator do not have the same select list. The RELATED_NAME column shows the alias of the first different select list item. The RELATED_NUM column shows the offset from the SELECT keyword to the start of this select list item.

How to fix the Error QSM-02150: select lists must be identical across the UNION operator ?

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

Restructure the materialized view query such that the respective sides of the UNION operator have identical select lists.