You can modify a relationship-driven inner join to create an outer join. For example, suppose that you use the Centrifugal Pump entity family, the Failure entity family, and the Asset Has Failure relationship family as query sources. If your system is configured such that the Asset Has Failure family relates the Centrifugal Pump family to the Failure family, GE Digital APM would create an inner join between the two entity families automatically.
If you ran the query using the default join, the results would include all Centrifugal Pump records that are linked to a Failure record. If you wanted to modify those results, however, to view all Centrifugal Pumps with their linked Failure records and all Centrifugal Pumps that did not have linked Failure records, you would need to modify the inner join to create an outer join. This would return Centrifugal Pumps with and without linked Failure records, but not Failure records without linked Centrifugal Pump records. For example, you could configure a query to show all the Centrifugal Pump records, where only three are linked to Failure records.
This type of join is considered a left join, as indicated by the following SQL code:
SELECT [Centrifugal Pump].[ASSET_ID_CHR] "Asset ID", [Failure].[EFAIL_ASSETID_CHR] "Failure ID"
FROM [Centrifugal Pump]RIGHT JOIN SUCC [Failure] ON {Asset Has Failure}
You could also decide to return all Failure records with their linked Centrifugal Pump records and all Failure records that do not have linked Centrifugal Pump records.
This type of join is considered a right join, as indicated by the following SQL code:
SELECT [Centrifugal Pump].[ASSET_ID_CHR] "Asset ID", [Failure].[EFAIL_ASSETID_CHR] "Failure ID"
FROM [Centrifugal Pump]RIGHT JOIN SUCC [Failure] ON {Asset Has Failure}
