Union Transformation

Union transformation is a multiple input group transformation that you can use to merge data from multiple pipelines or pipeline branches into one pipeline branch. It merges data from multiple sources similar to theUNION ALL SQL statement to Combine the results from two or more SQL statements.
Union Transformation Rules and Guidelines

• we can create multiple input groups, but only one output group.
• we can connect heterogeneous sources to a Union transformation.
• all input groups and the output group must have matching ports. The Precision, data type, and scale must be identical across all groups.
• The Union transformation does not remove duplicate rows. To remove Duplicate rows, we must add another transformation such as a Router or Filter Transformation.
• we cannot use a Sequence Generator or Update Strategy transformation upstream from a Union transformation.

Union Transformation Components
When we configure a Union transformation, define the following components:
Transformation tab: We can rename the transformation and add a description.
Properties tab: We can specify the tracing level.
Groups tab: We can create and delete input groups. The Designer displays groups we create on the Ports tab.
Group Ports tab: We can create and delete ports for the input groups. The Designer displays ports we create on the Ports tab.
We cannot modify the Ports, Initialization Properties, Metadata Extensions, or Port Attribute Definitions tabs in a Union transformation.
Create input groups on the Groups tab, and create ports on the Group Ports tab. We can create one or more input groups on the Groups tab. The Designer creates one output group by default. We cannot edit or delete the default output group.