Hi @anthony ,
Thanks for reaching out Microsoft Q&A!
concat
is not valid function or query parameter in Microsoft Graph for SharePoint.
Consider making use of SharePoint Calculated Fields, for this test I created a calculated field as below.
- In SharePoint List view I can see as shown here.
- Microsoft Graph API with above Calculated Field.
Hope this helps.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".