SSIS Basics: Using the Merge Join Transformation
SSIS is able to take sorted data from more than one OLE DB data source and merge them into one table which can then be sent to an OLE DB destination. This 'Merge Join' transformation works in a similar way to a SQL join by specifying a 'join key' relationship. this transformation can save a great deal of processing on the destination. Annette Allen, as usual, gives clear guidance on how to do it.