> For the complete documentation index, see [llms.txt](https://docs.whaly.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.whaly.io/data-management/workbench/model-data/flow-models/flow-steps/union.md).
# Union
## What does it do?
Union allows you to combine multiple datasets and models into one by matching the columns.
## How to use it ?
On any previously steps available in your editor select a step and click on **Combine -> Union**
## How to configure it ?
#### Union
In the form, start by selecting the dataset or models with want to union. If you see an empty list, drop a dataset or a model from the left panel into the canvas.
#### Columns
Select the columns your union step will output.
{% hint style="info" %}
Only the columns that have the same name and type in the two steps will be available
{% endhint %}
---
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