# Union
In this document, you’ll learn how to use the *Union* transformation in Astera Dataprep to combine datasets from different sources with an existing dataset in your Dataprep Recipe.
### Use Case
A company wants to combine its *North Sales* dataset with *South Sales* and *East Sales* datasets. These additional datasets may exist as files, shared project sources, or database tables. The objective is to consolidate them into a single unified dataset for analysis.
1. In the toolbar, click on *Union* and select the appropriate source type.
2. This will open the *Recipe Configuration – Union* panel. In this panel you can configure the source-specific settings (see tabs below).
{% tabs %}
{% tab title="Dataset" %}
* **Dataset:** Select the dataset you want to union with from the drop-down.
{% endtab %}
{% tab title="File " %}
* **Browse Path**: Use this to manually browse and select your source file.
* **Path from Variable**: Use this when your file path is dynamic and parameterized. To learn more about using variables click [here](/dataprep/variables.md#using-variables-in-recipes).
For this use case, we’ll use the *Browse Path* option.
{% endtab %}
{% tab title="Project Source" %}
* **Filter Source:** Choose the type of source you want to use. You can filter by type or simply select *All*.
* **Shared Source:** From the drop-down, select the project source dataset you want to join.
{% endtab %}
{% tab title="Database Table" %}
* **Connection Name:** Select the shared connection you want to use. The drop-down lists all shared connections available in the project.
* **Table:** From the drop-down, choose the database table you want to union with. In this example, we’ll select the *southsales* table.
{% endtab %}
{% endtabs %}
3. Provide a name for the union dataset (or keep the default name).
4. Choose a *Union Type*:
* **Matching:** Returns only the fields that are present in both datasets.
* **All:** Returns all fields from both datasets.
* **Remaining:** Returns fields present in the current dataset along with the fields present in both datasets.
5. Once you’re done, click *Apply.* The result will appear in the grid.
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