Union

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The Union transform combines the rows from two tables that have matching columns.

If the two inputs come from the same data connector, and the data provider supports union statements, the union will be automatically included as part of the query sent to the database, unless the transform is preceded by another that must be executed by Dundas BI.

Transform - Union
Transform - Union

1. Input

The Union transform requires at least two inputs, and more than two are supported.

For example, the input could be data coming from two different Excel sheets, which have corresponding columns:

2. Configure

In the Union configuration dialog, there are separate settings for each input.

For the first input, select which elements should be included in this transform. You can exclude elements that don't have matching columns in the other inputs.

Primary input settings
Primary input settings

Change the Inputs dropdown to select each other input, and click to expand each column's Mapping Element. Ensure each column is mapped correctly to the matching column in the other input. This is especially important if the column names did not match.

First column mapping
First column mapping

Second column mapping
Second column mapping

Extra elements that don't have matching columns in the other inputs can be un-checked to exclude them.

There is an Include Duplicate Rows option, which applies to all inputs.

Include duplicate rows
Include duplicate rows

3. Output

The output combines the rows from all of the inputs.

The figure below illustrates the output in our example:

Union output example
Union output example

The figure below illustrates the output when the duplicate rows are excluded:

Duplicate rows excluded
Duplicate rows excluded

4. See also

Dundas Data Visualization, Inc.
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Toronto, ON, Canada
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North America: 1.800.463.1492
International: 1.416.467.5100

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