How to add an extra column to the existing table in power bi query editor

Question

I am trying to add an extra column to the existing table in power bi query editor, but not getting any idea how can I do it. Can anyone explain the process?

Answer 1

Hi,

To create a custom column, we need to follow some steps:

1. First, we need to Launch Power BI Desktop and load some data.
2. Once you launch Power BI Desktop then, from the Home tab on the ribbon, select Edit Queries, and then select Edit Queries from the menu.
3. Then, from the Add Column tab on the ribbon, select Custom Column. 
4. Once you select Custom Column, then you will get to see a list of columns and in the Available columns list on the right.
5. You can see New column name box. You can rename this column.
6. In the Custom column formula box. You create these queries by building the formula on which your new custom column is defined.

To create formulas for your custom column:

1. Select a column from the Available columns list on the right, and then select Insert below the list to add them to the custom column formula.
2. As you enter the formula and build your column, note the indicator in the bottom of the Add Custom Column window.
3. Select OK.

*Power BI Desktop adds your custom column to the model, and adds the Added Custom step to your query's Applied Steps list in Query Settings.

For more information you can follow this docs, 

https://docs.microsoft.com/en-us/power-bi/desktop-add-custom-column

Answer 2

Use Query Editor to add a custom column

To start creating a custom column, follow these steps:

1. Launch Power BI Desktop and load some data.

2. From the Home tab on the ribbon, select Edit Queries, and then select Edit Queries from the menu.

3. From the Add Column tab on the ribbon, select Custom Column.

4. The Add Custom Column window appears.

5. The Add Custom Column window

   The Add Custom Column window has the following features:

6. A list of available columns, in the Available columns list on the right.

7. The initial name of your custom column, in the New column name box. You can rename this column.

8. PowerQuery M formula queries, in the Custom column formula box. You create these queries by building the formula on which your new custom column is defined.

9. Create formulas for your custom column

10. Select a column from the Available columns list on the right, and then select Insert below the list to add them to the custom column formula. You can also add a column by double-clicking it in the list.

11. As you enter the formula and build your column, note the indicator in the bottom of the Add Custom Column window.

    If there are no errors, you'll see a green check mark and the message No syntax errors have been detected.

12. If there's a syntax error, you'll see a yellow warning icon, along with a link to where the error occurred in your formula.

13. Select OK.

    Power BI Desktop adds your custom column to the model, and adds the Added Custom step to your query's Applied Steps list in Query Settings.

14. To modify your custom column, double-click the Added Custom step in the Applied Steps list.

    The Add Custom Column window appears with the custom column formula you created.

Answer 3

Click on edit queries after loading source file to power bi.

1. Using 'Enter Data' button entered sample data you provided and created new table. ...
2. Expand Table - In the original table expand the merged table. ...
3. You can always change data(add new columns/rows) manually in new table by clicking on gear button next to source.