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Self Join


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self-join

A join in which records from a table are combined with other records from the same table when there are matching values in the joined fields. A self-join can be an inner join or an outer join.

-- From the MS MSDN SQL Server Glossary
Most commonly when there is a foreign key field that points to the primary key of the same table. A classic example is an Employee table containing a Manager field. The Manager value for one employee points to the record of the employee's manager (who is also an employee).
For some other examples of using Self - Joins see http://www.networksplus.net/cschreiner/OutFoxed11.html

Category Definitions
Contributors: Randy Pearson
( Topic last updated: 1999.11.30 10:54:57 AM )