Updating/Adding data

[user10122005]

Hey! Could anyone please help me:

I have a 28k row table of records from 2023 to May 2025 on my Power Bi report and need to update some of the data and add new data that ranges till July 2025 to it from another Excel/CSV file. 

Both tables look the same (Customer (name), Date- Year, Date -Month (text), Revenue columns) except the PBI table has 2 additional columns (that can be created from the other columns in the table). One of the additional columns outputs the earliest date a customer has been active on.

How can I update/add the new data to the table in PBI? Can I update it if they dont have the same nb of columns? Do I have to add the columns to the excel file? If yes, how do I do that for the column that tracks the customer's earliest record date? 

Thanks in advance,

Yasmine

[v-priyankata]

Hi @user10122005 

Thank you for reaching out to the Microsoft Fabric Forum Community.

@MasonMA @rohit1991  Thanks for the inputs.

I hope the information provided by users was helpful. If you still have questions, please don't hesitate to reach out to the community.

[rohit1991]

Hi @user10122005 ,

This is a pretty common scenario, and luckily Power BI is really flexible about combining data from multiple sources, even when the columns don’t match up perfectly.

Here’s what I’d suggest (I’ve had to do this a few times myself):

1. Append Queries in Power Query: In Power Query, use “Append Queries” to stack your old and new tables together. Power BI matches columns by name, so any columns that are missing in one table will just get filled with blanks/nulls. No need to mess around with your original Excel or CSV files to add columns they can be different and Power BI will handle it.
   
   

2. Keep your original table/query name: If you already have measures and visuals tied to your existing table, just make sure your combined table ends up with the same name as before. That way, all your reports, visuals, and measures will keep working without having to re-link anything.
   
   

3. Earliest Customer Date column: You don’t need this in your Excel/CSV. You can calculate it directly in Power Query using “Group By”, or as a DAX measure in Power BI. For example: Earliest Date = CALCULATE(MIN('Table'[Date]), ALLEXCEPT('Table', 'Table'[Customer]))
   
   

4. Check for duplicates: If there’s any risk of overlap between your old and new data, it’s a good idea to remove duplicates after appending. In Power Query, just select the right columns and use the “Remove Duplicates” feature.
   
   

5. Column names: If the columns that should line up have slightly different names in each table, just rename them in Power Query before you append.

You don’t need to update your Excel/CSV files to have all the same columns, and you won’t break your visuals/measures as long as you keep the main table name the same in Power Query.

[MasonMA]

@rohit1991 Would help if you could share something new or a different perspective .

[rohit1991]

Hi @user10122005 , ,

To add a different perspective, If you have a lot of measures, calculated columns, or complex model relationships already built on your original table, one way to streamline updates is to stage your new data in a separate query first (without appending immediately). This lets you preview, transform, or even troubleshoot the new rows before committing them to the combined table.

Also, if your new data might occasionally have different columns, you can use Power Query’s “Choose Columns” or “Column Names” steps before appending, to auto-align structure even if source columns are sometimes missing or reordered.

And for tracking earliest customer records, if you want it to persist automatically; You can keep a rolling summary table of customer min dates using Group By in Power Query, Or, as a DAX alternative, create a summary table that always recalculates the earliest date across both sources after each refresh.

[MasonMA]

@rohit1991 

I was wondering if there was a different solution other than appending these queries? 

[MasonMA]

Hi @user10122005 

Consider using Append Queries in Power Query to combine your tables. And yes you can update it even if they dont have same numbers of column. Power BI allows appending tables with different columns BUT columns not present in one table will be filled with null.

As for 'how to do that for the column that tracks the customer's earliest record date', there are ways to make this dramatic either in Power using GROUP BY or adding a Calculated Column in Power BI.

Yoo may also want to check these Youtube tutorials showing techniques on how to dynamically combine csv/excel files in Power Query.

https://www.youtube.com/watch?v=vCwqF6MHd24

https://www.youtube.com/watch?v=PWp5Aes9ZJc

Hope this helps:) 

[user10122005]

Hey @MasonMA , thanks for your answer. However, I have a lot of measures tied to my initial tabel and would like to update them as well with the new data. I thought keeping the first table as their reference is the best as it would too much of a hassle to update all of them. The method you gave me helps creating a new table with both tables combined right?

[MasonMA]

Hi @user10122005 

Yes, it's creating a new table if your 'Append Queries as New', which would combine all your tables in a new Tables, or consider appending new tables onto your Original table(and using these queries as Staging Queries and disable loading of these new tables once done). It won't break your query, as long as you append the data in Power Query and keep the name of your final combined query the same as your original table. That way, your existing measures and visuals won’t break because the table name they refer to stays the same.