# Concatenate columns transform
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The Concatenate transform allows you to build a new string column using the values of other columns with an optional spacer. For example, if we define a concatenated column “date” as the concatenation of “year”, “month” and “day” (in that order) with “-” as the spacer, we would get:


| day | month | year | date | 
| --- | --- | --- | --- | 
| 01 | 01 | 2020 | 2020-01-01 | 
| 02 | 01 | 2020 | 2020-01-02 | 
| 03 | 01 | 2020 | 2020-01-02 | 
| 04 | 01 | 2020 | 2020-01-02 | 

**To add a Concatenate Columns transform:**

1. Navigate to your visual ETL job in Amazon SageMaker Unified Studio.

1. Choose the plus icon to open the **Add nodes** menu.

1. Under **Transforms**, choose **Concatenate Columns**.

1. Select the diagram to add the node to your visual ETL job.

1. Select the node on the diagram to view details about the transform.

1. Under **Concatenated column**, enter the name of a new column that will be generated.

1. Under **Columns**, select the input columns.

1. (Optional) Under **Spacer**, enter a string to place between concatenated fields.

1. (Optional) Under **Null value**, enter the string to use when a column value is null.