An outer join allows you to return records that satisfy the join conditions and records from one family for which there are no matching records in the other family.
You can modify the default inner join to manually create an outer join for families that are related through a relationship family.
The following table shows the line styles that appear in the design canvas to represent GE Digital outer joins.
| Join Type | Line Style |
|---|---|
| GE Digital Outer Left Join |
|
| GE Digital Outer Right Join |
|
If you use two unrelated families as query sources, such as the Centrifugal Pump family and the Rotary Pump family, you can create an outer join to view all Centrifugal Pumps and Rotating Pumps whose manufacturer is the same and all Centrifugal Pumps with a different manufacturer. If the Centrifugal Pump family was added as a query source as Table #1 and the Rotary Pump family was added as Table #2, this would create a left join, which would be indicated in the SQL code.
On the other hand, if you wanted to view all Rotary Pumps and Centrifugal Pumps whose manufacturer is the same and all Rotary Pumps with a different manufacturer, you would create a right join, which would be indicated in the SQL code.
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}
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