SSIS Merge Transformation

[[articles:SQL Server Integration Services (SSIS)|Integration Services]] uses transformations to manipulate data during an [[articles:Extract Transform Load (ETL)|ETL]] dataflow. Transformations can be used in [[articles:SSIS Dataflow Task|Data Flow Tasks]], between data source and destination components, or other transformations.

Sometimes sorted data flows can be a key requirement, especially before joining data with the [[articles:SSIS Merge Join Transformation|Merge Join transformation]]. Two, previously sorted data flows can be merged into a single, still sorted one if they have the same sort metadata (the type and length/precision are the same, in the same order in both inputs).

This transformation supports exactly two inputs and a regular output. It does not support an error output.

The Merge is a partially blocking (asynchronous) transformation: the output is copied into new buffers, the input buffers won't be reused.

If sorting is not a requirement, consider using the [[articles:SSIS Union All Transformation|Union All transformation]] only. If more than two inputs should have been merged, use a Union All first, then a [[articles:SSIS Sort Transformation|Sort transformation]] instead of Merge.

For more detailed information on this transformation, please refer to this MSDN article.
For the complete list of SSIS transformations, check [[articles:SSIS: List of Transformations|this Wiki article]].