Power Automate – Read large Excel files within seconds without creating tables using Microsoft Graph

In Microsoft Flow it is possible to use the Excel connectors to read data form a spreadsheet. When you want to read large Excel files you might run into issues.

Excel connector issues

There few major issues with the excel connector are:

  1.  You data needs to exist within Excel Tables.
  2. Large tables take long to load. (4000 rows takes about 2 minutes)
  3. The Excel connector likes hard coded names for sites, libraries and Excel files.
  4. Excel files get locked as you configure flows. And it can take a while for the locks to be removed.

If the above is not a problem please feel free to create a flow like this:

Get Tables and List Rows actions

Read large Excel files

If you want more however you might want to look into the graph API when you read large Excel files. With the help of Flow Ninja, John Liu‘s post on twitter I got this all working.

I started with setting up my app permissions which gave me a Tenant ID, Client Id and Secret which I then used in 3 variables. If you need some help setting this up you could look at the infoPulse site.

Now I’m having to Collect the site details from MS Graph. This can be done by configuring an HTTP action as shown below. After the v1.0/sites bit simply supply the url of your subsite.

HTTP request calling MS Graph to Read large Excel files

This now gives the ID of the site that we need to get the list of the lists an libraries that we are interested in. Remember you will need to specify the same authentication bits as in the previous HTTP call.

To get the ID ( if not available in dynamic content you can use the following expression.


HTTP request calling MS Graph getting lists

Now I can use the ID returned for the library. I used a compose in between these actions to hold the library details.

To create this compose action you might have to use a filter action to select the right document library from the HTTP 3 action.

For help on filtering arrays in power automate please look at my post about array filtering. this should now give you the single library id. I’ve created a compose action called Compose 2 to hold this library record.

HTTP request calling MS Graph reading range

This now give me the fully generic solution that helps me copy the flow between my Dev, UAT and production environment

Generic graph call

Then finally I can run through the Excel data with an Apply to each step. In this case I only did a Compose to collect each row but most likely you would now do something with the data like updating a SharePoint list.

Step through the data from my excel

  1. No need for Excel Tables.
  2. Large tables are quick to load. (4000 rows takes about 4 seconds)
  3. My flow is a generic process that is easy to copy between environments
  4. No file locking on my Excel files.

15 thoughts on “Power Automate – Read large Excel files within seconds without creating tables using Microsoft Graph

  1. commented on January 22, 2020 by jo moma

    not enough info

  2. commented on February 3, 2020 by Farhan Rob

    Hi Pieter,

    What is the trigger of this flow?

    • Hi Farhan,
      You can use any trigger you like. The trigger isn’t really relevant. What should start your process?

      • commented on February 3, 2020 by Farhan Rob

        Thanks for the quick response Pieter.

        I have an automated process from SAP to send an Excel sheet as an attachment to my email nightly. The issue arises that the data is not in a table within the Excel file and there is no way to configure that. So I stumbled upon your post and how this HTTP method can be used to decipher data that is not within a table.

        I’d love if you could give me an example of how to utilize this with the problem statement that I have described above if you have the time.


      • If the excel appears as an attachment to an email address that has it sole purpose of receiving these emails then you could trigger on the email arriving.

        Then get the flow to copy the attachment to a file in SharePoint and then use MS graph to read a range from the excel file.

      • commented on February 3, 2020 by Farhan Rob

        Is this range dynamic? Or is it possible to set a maximal range to capture all the data regardless of column length.

      • No, you will have to set it to range values.

        So if your excel has a maximum of 200 rows then you would have to set it to read 200 rows. It might mean that you end up with empty rows.

  3. commented on June 10, 2020 by Chad

    Instead of infopulse, I found this showed how to use the new azure site.

  4. commented on June 24, 2020 by Phil Hemingway

    There is definitely not enough info to use this article as a reference. “This now gives the ID” … not for me, it does not. I do not have an object for ID from which to choose, while in your screenshot, you are able to select ID. So I must manually type in the hostname-SiteID-WebID. Then, it would be very helpful if you would include explanation and a screenshot of your compose action. It would also help if you explained the breakdown of the URI in the last HTTP call. And lastly, where did “formulas” come from in your “Apply to each 4” action? These instructions seem like they could be helpful and I thank you for putting this together, but they are just too incomplete and confusing.

    • commented on June 25, 2020 by Pieter Veenstra

      Hi Phil,

      If the ID doesn’t appear in the dynamic content then the tooltip in the screenshot shows the expression needed. Anyway, I will include the expression in the post as code as well.

  5. commented on June 25, 2020 by Phil Hemingway

    Thank you very much, Pieter. I appreciate that. I’m sure you can tell that I’m somewhat new to Flow. It’s always tough as a newbie to connect the dots.

    • commented on June 25, 2020 by Pieter Veenstra

      Thank you for the feedback.if you need any further help or if you find any other incomplete posts please feel free to contact me.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: