| ERROR | select lists must be identical across the UNION operator |
| CAUSE | 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. |
| ACTION | Restructure the materialized view query such that the respective sides of the UNION operator have identical select lists. |