Difference between revisions of "Outer Joins"
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'''An outer join can be created by using the WHERE clause with an outer join operator or the OUTER JOIN keywords''' | '''An outer join can be created by using the WHERE clause with an outer join operator or the OUTER JOIN keywords''' | ||
===limitations when using the traditional approach to outer joins:=== | |||
* The outer join operator can be used for only one table in the joining condition.In other words, you can’t create NULL rows in both tables at the same time. | * The outer join operator can be used for only one table in the joining condition.In other words, you can’t create NULL rows in both tables at the same time. | ||
Revision as of 00:56, 24 October 2017
An outer join is created when records needs to be included in the results without having a corresponding records in the join tables. These records are matched with the NULL records so that they are included in the output
An outer join can be created by using the WHERE clause with an outer join operator or the OUTER JOIN keywords
limitations when using the traditional approach to outer joins:
- The outer join operator can be used for only one table in the joining condition.In other words, you can’t create NULL rows in both tables at the same time.
- A condition that includes the outer join operator can’t use the IN or ORoperator.