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# Rename, format and sort columns in Mammoth

> Rename a column, format numbers as currency or percent, change date formats, sort, hide and freeze columns in Mammoth, and undo them in Display Changes.

Renaming, formatting, sorting, hiding and reordering columns are Display Changes: they change how a View looks, never the data, and they add no pipeline task. You make most of them from a column's 3-dot menu in the data grid, and review or undo them in **Display Changes (n)** at the bottom of the Pipeline panel. Text formatting (case and whitespace) is the exception: it adds a Text Formatting task.

## How Display Changes differ from pipeline tasks

- View-specific: each View has its own Display Changes. A new View starts with none.
- They apply at once in most cases. Number format changes need **Apply** in the formatting panel.
- They add no pipeline tasks: the Pipeline panel is unaffected.
- Renamed columns show their new names in the grid, pipeline task dropdowns and exports.
- They aren't part of automation: they are presentation only and don't run in scheduled pipelines.

For pipeline tasks, see [How the pipeline works](https://mammoth.io/docs/learn/clean-and-shape/how-the-pipeline-works/).

## Rename a column

There is no Rename Column function in the Transform menu. Rename from the grid instead:

1. Double-click the column header, or open its 3-dot menu and choose **Rename Column**.
2. Type the new name in the inline box.
3. Press Enter.

![Column menu showing rename column option highlighted](https://mammoth.io/docs/images/20260417_105237_Columnmenushowingrenamecolumnoptionhighlighted1.webp)

![Column header showing the inline rename field](https://mammoth.io/docs/images/20260508_155745_Columnheadershowingtheinlinerenamefield.webp)

The new name applies at once, in this View only. Other Views still use the original name. Renaming here and in the Column browser is the same thing: both set a display name for this View.

To undo it, open the column menu and choose **Revert to original column name**. That option appears only after a rename.

**Rename Column** is disabled while the transformation info panel is open or while any pipeline task is in error. **Hide Column** and **Revert to original column name** are also disabled while a task is in error.

## Format a number column as currency, percent or decimals

On a NUMERIC column, the formatter sits inline in the column menu under **Formatting**. It has a row of icon buttons with no text labels.

![Formatting panel open for a numeric column showing currency](https://mammoth.io/docs/images/20260417_105332_Formattingpanelopenforanumericcolumnshowingcurrency1.webp)

| Control | What it does |
| --- | --- |
| Separator | Turns thousand separators on or off (1,234,567 or 1234567). On by default. |
| Percentage | Shows numbers as percentages (0.45 shows as 45%). |
| Currency | Opens a picker: **$** (USD), **€** (EUR), **¥** (YEN), **£** (GBP) or **₹** (INR). |
| Decimal precision | Left and right chevrons step the visible decimal places, up to 5. The default is 2. |
| **Apply** | Saves the format. Enabled only when the settings differ from the saved format. |
| **Reset** | Puts back the defaults: separator on, no currency, no percentage, 2 decimals. Shown only when the format differs from the default (tooltip "Reset to original formatting"). |

Currency and percentage can't be used together: turning one on turns the other off.

On a Currency, Percentage or ID column, some buttons are greyed out with the note "Set by the column's type". For example, a Currency column can't show as a percentage, and an ID column has no thousands separator. **Apply** leaves those settings alone, and **Reset** brings back what the type decides. To change them, change the column's type. See [Column types, IDs, currency and percentages](https://mammoth.io/docs/learn/clean-and-shape/column-types/).

Number formatting changes only how values look in this View. Other Views keep their own formatting.

## Change how a date column is displayed

1. Open the date column's 3-dot menu and hover or click **Format**.
2. Choose a date type: **Universal**, **US** or **UK**.
3. A list of formats appears, each showing today's date as a live preview. Click one to apply it at once.

![Formatting panel open for a date column showing the date format dropdown](https://mammoth.io/docs/images/20260417_105401_Formattingpanelopenforadatecolumnshowingthedateformatdropdown1.webp)

To turn text into real dates, use Convert Column Type instead. See [Convert text to dates and numbers](https://mammoth.io/docs/learn/clean-and-shape/convert-column-type/).

## Change text case or trim spaces from the column menu

On a TEXT column, **Format** opens a flyout. Unlike number and date formatting, this adds a Text Formatting task to the pipeline and changes the column's values. Everyone using this View sees the result.

To change text case:

1. Tick **Change case to**.
2. Pick **UPPER**, **lower** or **Capitalized**.
3. Click **Apply**.

To remove extra spaces and tabs:

1. Tick **Normalize whitespace**.
2. Click **Apply**.

**Apply** stays disabled until you tick at least one option. **More options** opens the full Text Formatting panel with your choices filled in. See [Work with text and JSON](https://mammoth.io/docs/learn/clean-and-shape/text-and-json/).

### Show hidden spaces in a text column

**Show Whitespaces** is a checkbox in the main column menu (not in the Format flyout), on TEXT columns only. Tick it to show spaces and special characters as visible symbols throughout the column. Untick it to hide them. It helps when leading spaces or tabs are spoiling a match.

## Sort rows by one or more columns

To sort by one column:

1. Open the column's 3-dot menu.
2. Choose **Ascending** or **Descending** in the Sort dropdown. The grid reorders at once.

The column menu sorts by one column at a time; a sort on another column replaces it. To sort by several columns, click **Sort by** in the grid footer. It shows the active sort (or "Default") and opens the Sort Columns dialog, where **Add another sort** adds a level. An X beside **Sort by** clears the sort without opening Display Changes.

![Data grid footer showing 153 rows, Showing all 21 columns, and a Sort by customer_age chip with a close icon](https://mammoth.io/docs/images/20260417_105308_-_Datagridfootershowing_Sortby_1.webp)

Sorting is a Display Change, not a pipeline task. It is saved with the View, stays after a refresh, and is listed under **Grid Changes** in Display Changes. There is no Sort pipeline task. If a calculation needs a row order, use **Add Sort** inside functions such as Fill Missing Values or Window Function; that order is saved with the task.

## Freeze a column so it stays visible

1. Open the column's 3-dot menu.
2. Tick **Freeze "order_id"** (the label shows the column's name).
3. The column is pinned to the left of the grid and stays visible as you scroll right.

Untick it to unfreeze. You can freeze more than one column, though each one leaves less room to scroll the rest.

Freezing isn't a Display Change. It is your personal setting for this View: it stays after a refresh, doesn't appear in Display Changes, and other users don't see it.

## Hide or reorder columns

- **Hide a column**: open its 3-dot menu and choose **Hide Column**. The data stays and the column is still available in pipeline task dropdowns. Exports leave out hidden columns unless the export's **Include hidden columns** option is selected. Other Views are unaffected.
- **Unhide a column**: use the [Column browser](https://mammoth.io/docs/learn/explore/column-browser/) (click the column count at the bottom of the View) or revert it in Display Changes.
- **Reorder columns**: drag a header left or right. It applies at once.

To take a column out of the data for later tasks, use Remove Column instead. See [Add, split, copy and delete columns](https://mammoth.io/docs/learn/clean-and-shape/manage-columns/).

## Review and undo changes in Display Changes

**Display Changes (n)** appears at the bottom of the Pipeline panel once at least one Display Change is active. Hover it for a breakdown, for example "Column Rename (1), Format Changes (2), Grid Changes (2)."

![Bottom of the Pipeline panel with a Display Changes (6) bar and a tooltip: Column Rename 2, Format Changes 2, Grid Changes 2](https://mammoth.io/docs/images/20260417_113612_BottomofPipelinepanelshowing_DisplayChanges51.webp)

Click it to open the dialog. It has three sections:

| Section | What it lists |
| --- | --- |
| **Column Rename** | Every renamed column as original name → new name |
| **Format Changes** | Every column with a display format, with before and after |
| **Grid Changes** | Active sorting, column order and hidden columns |

![Display Changes dialog Column Rename tab, mapping customer_id to customer_id_updated and order_status to order_status_renamed](https://mammoth.io/docs/images/20260417_113644_DisplayChangesmodalColumnRenametabshowing_customer_idcustomer_id_updated1.webp)

![Display Changes dialog Format Changes tab, showing order_date DD-Mon-YYYY to YYYY-MM-DD and order_amount 1000 to €1000](https://mammoth.io/docs/images/20260417_113704_DisplayChangesmodalFormatChangestabshowing_order_date_DD-Mon-YYYYYYYY-MM-DD1.webp)

![Display Changes modal Grid Changes tab showing Sorting](https://mammoth.io/docs/images/20260417_113722_DisplayChangesmodalGridChangestabshowingSorting1.webp)

To undo changes:

1. Click the X on an entry to revert it, or click **Undo changes** to revert a whole section.
2. Click the submit button. It reads **Save changes** and is disabled until you change something; after that it reads, for example, **Apply 2 changes**.

## Troubleshooting display changes

| Symptom | Cause | Fix |
| --- | --- | --- |
| A sort disappeared after a refresh | It should persist as a Display Change | Check **Grid Changes** in Display Changes |
| **Rename Column** is greyed out | The transformation info panel is open, or a task is in error | Close the panel, or fix or remove the failing task |
| Format or sort changes are ignored | A pipeline task is in error | Fix or remove the failing task, then try again |
| Number format didn't change | **Apply** wasn't clicked | Reopen the menu and click **Apply** |
| Currency and percentage won't both stay on | They can't be used together | Pick one |
| A number format button is greyed out with "Set by the column's type" | The column is a Currency, Percentage or ID column | Change the column's type |

## Related

- [Work in the data grid](https://mammoth.io/docs/learn/clean-and-shape/data-grid/): the full column menu and bulk actions on several columns.
- [Column types, IDs, currency and percentages](https://mammoth.io/docs/learn/clean-and-shape/column-types/): why some format buttons are locked.
- [Browse columns](https://mammoth.io/docs/learn/explore/column-browser/): show, hide and reorder all columns at once.
- [Download data](https://mammoth.io/docs/learn/share-and-export/download/): how hidden columns and new names reach an export.
- [Highlight values with colour](https://mammoth.io/docs/learn/clean-and-shape/highlight-values/): colour cells by rule without changing data.

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Source: https://mammoth.io/docs/learn/clean-and-shape/rename-format-sort.md · Updated: 2026-11-08