Refreshing just one column.

[mwm39]

Hi all,

I have weekly  100 CSV files consolidated as below for a dashboard

every week, this table is refreshed with new weeks Data.

Issue: Sometime previous week's data is changed at source level and when this table is  refreshes, it changes previous weeks result as well. Is there a way where we can refresh only reporting weeks results and keep previous weeks results locked?. For example when week 19 results are updated, week1-18 data should remain same even if it has changed at source level. 

I was thinking to creaate two similar tables TableA ( to Refresh/update every week) Table b. (To refresh only relevant Week from Table A) but dont know how to implement it. Any ideas pls. Thanks

[Shahid12523]

Power BI always reloads everything → you can’t refresh only one column.

How to Fixes:

Reshape to long format (Cost Center | Week | Value) → enable Incremental Refresh so only recent weeks update.

Keep two tables → one frozen (old weeks, refresh off) + one live (latest weeks, refresh on) → then append.

Archive weekly CSVs in separate files/folders → append all to preserve history.

Best option: reshape to long format + use Incremental Refresh.

[AnkitKukreja]

Hi! @mwm39 

Then you need a small indentifier in your file like a week column and then you can create a simple Power Automate flow to keep your data.

• • Read the file.
  • Extract only current week’s data.
  • Update Table in a Excel file, replacing only current week’s rows.

[AnkitKukreja]

Hi! @mwm39 
You can use incremental refresh this will ensure your old data is in the memory and only last few days or week is being refreshed as needed -https://learn.microsoft.com/en-us/power-bi/connect-data/incremental-refresh-overview.

Or you can setup a code with Power query or Power automate as well. If you need idea around these then you might have to explain your setup like; what is the source and how is the structure, I believe if it's csv files then you might be keeping it in SharePoint or a folder, so what files you have and do you append within the files or drop new files in the folder?

[mwm39]

Thanks for your reply Ankut. Every week when cost centers send results to a SP folder the previous week file is replaced with current week's file . So issue is some times within this current week file, results for previous week is altered. Incremental refresh will not work because files are not appended or added rather replaced with a new file. 

[v-sshirivolu]

Hi @mwm39  ,
Thanks for your clarification. Incremental refresh will not work here since the files are being replaced, not appended. Incremental refresh requires additive rows with a stable date column.(docs).

Try These Workarounds :

Archive each weekly file with a timestamp (e.g., via Power Automate) so history is preserved.

Use a self referencing merge in Power Query to retain past data while refreshing only the current week.

Store data in a staging location (SQL/SharePoint/Dataverse) that accumulates weekly snapshots for Power BI.

Microsoft Docs :

Incremental refresh in Power BI

Dataflows and incremental refresh

Automate file management with Power Automate

[v-sshirivolu]

HI @mwm39 ,
I hope the information provided above assists you in resolving the issue. If you have any additional questions or concerns, please do not hesitate to contact us. We are here to support you and will be happy to help with any further assistance you may need.