Adding removed columns to an existing table after a lot of transformation steps[joins,merge,append]

[Anonymous]

Hi Team,

Greetings.

Hope you all are doing fine.

I have 1 issue here which I am stuck at.If anyone could help urgently :

Background

I imported a table(Let's say A) from a database and while transforming it, removed a few columns as we didn't need them then and saved it.(Let's say it B)

Now,This table(B) furthermore underwent joins and merges with other tables(Other sources) to bring in the required data and prepare the dataset.It has become a huge dataset as we speak.

Now, we need to re import an old column to the concerned table(B).[Meaning I need to add one of the columns I deleted in the first step]

I did the below thing :

Imported the old major table again(A) and did a left outer join with the existing table(B) to bring in the column after expanding it i.e B Left Outer Join A 

It's all happening smoothly, we can see the columns,data but as soon as you click "Close and Apply" , it runs for 2 hours and then Power Bi crashes or throws error that a previous table needs to be updated.I tried this 3-4 times and the same issue happens.

Is there any way to import the lost column, save it,keep the integrity of the dataset[Not affecting existing Joins etc] and not crash power bi so that we can actually use it for my visualizations ?

Will the dataset be compromised as I am adding new columns post a lot of transformation steps ?

I am an absolute novice to Power BI and is scared to use the advance query feature.

Do let me know If I was able to explain the issue.Any help would be greatly appreciated as always.

[Fowmy · Accepted solution]

@Anonymous 

As I understood, you re-did the whole import and transformation process as soon as you faced the issues, which would not be necessary. 

If you need to bring back a column that you removed in the process, go to the step where your preformed the removal, It could be Remove Column or Remove Other Column.
Include the column you removed by clicking on the gear icon on the step. Then, check other steps for any error and fix.
This should should help.

If above doesn't work, save the affected queries (M code), delete the affected query, now recreate the query using the previously saved M Code.

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[artemus · Accepted solution]

What you want to do isL

1. Go to the step where you removed the columns

2. Right click and choose - Extract previous steps

3, In the newly created query (with the previous step) right click it and unselect load into report

4. Right click the new query and select Reference.

5. Now in that query build your new table.

[Fowmy · Accepted solution]

@Anonymous 

As I understood, you re-did the whole import and transformation process as soon as you faced the issues, which would not be necessary. 

If you need to bring back a column that you removed in the process, go to the step where your preformed the removal, It could be Remove Column or Remove Other Column.
Include the column you removed by clicking on the gear icon on the step. Then, check other steps for any error and fix.
This should should help.

If above doesn't work, save the affected queries (M code), delete the affected query, now recreate the query using the previously saved M Code.

________________________

Did I answer your question? Mark this post as a solution, this will help others!.

Click on the Thumbs-Up icon on the right if you like this reply 🙂

YouTube, LinkedIn