# Select & Alter tab

![Select & Alter tab in Select values](/files/7hxLHNT2n66iH4dN4iDJ)

The table in this tab contains the following columns for fields you want to select, rename, or change length and precision.

| Column        | Description                                                                    |
| ------------- | ------------------------------------------------------------------------------ |
| **Fieldname** | The name of the field from the input stream.                                   |
| **Rename to** | The new name of the field. Leave blank if you do not wish to rename the field. |
| **Length**    | The length of the field.                                                       |
| **Precision** | The number of floating point digits for number-type fields.                    |

Use **Get fields to select** to add all fields from the input stream(s).

Use **Edit Mapping** to open the Edit Mapping dialog.

Select the **Include unspecified fields, ordered by name option** to include fields in the input stream(s) that are not explicitly selected in the **Fields** section.


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