When you try to update cells in Excel using Power Automate you could use the Update a row action.
Update a cell in Excel
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In the past I’ve used MS Graph to do things with Excel spreadsheets with Flow.
When you use the update a row action to update cells in Excel, like with all other actions in this connector, you will need a table in your Excel spreadsheet. One additional requirement is needed for the update a row action.
You will need a key column with unique values.
In my example below I created a column key and populate this column with a number.

Now as I run my flow my row with the key equals 1 is updated.

Unique Key column
It is important that you have a Key column that is unique. When I updated the row with Key set to 1 while I had multiple rows having a key of 1 only the first row was updated.

Therefore make sure that you key column is unique and then this update a row action can be very useful.
i need to know what’s the last key value for row in key column .. i need to create a flow . one excel file updated with new row .. or any cell updated .. to send me Notification by email
Hi Tamer,
i noticed that too. When you create a 3 column table in Excel the Power Platform adds another column with a unique key. I don’t think that the values really matter as long as that column is unique within the table.
Hi Pieter,
Good post. This is close to what I’m trying to do myself, but not quite. I simply want to update all rows in an Excel table using “List rows present in a table” followed by “Apply to each”. However it appears that the only way to then update the row is to use “Update a row”.
The problem with using “Update a row” is that is that you have to define the location of the table again after having just done so for “List rows present in a table”. And in the process having to provide a key to uniquely identify the row to be updated. This makes no sense to me. It should already know what row is to be updated, i.e., the current row in “Apply to each”. And by having to define what table and row again, you can only update tables that have an unique value column.
What am I missing here?
Please have a look at the following post:
https://sharepains.com/2020/08/04/populate-excel-template-power-automate/
Using MS Graph I have covered all update scenarios.
Hi Pieter,
When updating a row of excel, I am using the dynamic SharePoint address from power apps. My table name is fixed always. I want to give the document Library as a custom Value. If i give the custom value as ID of the document library Table or its name like “Documents”. It doesn’t work. It is having some unique ID like this “b!IBThIWvJLE2cpXR4vXSgWAz4mAwzdOFMtFvvN_BOStD_-L5GIQ_WQY2RKhBib1nu”.
Is there any way to fetch that??
You should use Microsoft Graph to get that done. The post below will give you the detailed steps for this.
https://sharepains.com/2020/08/04/populate-excel-template-power-automate/
In this post I didn’t use tables but there is no reason why you couldn’t use the tables that the Graph API offers.