Hi Max,
Thank you for your posting!
Regarding this issue, I understand that you would like to show the
connecting User ID and the related roles in a report so that you can check
the information.
If I have misunderstood, please let me know.

For retrieving the user's identity, you can directly use the expression
"=User!UserID"; for getting the related roles, you can query ReportServer
database with the following T-SQL statement:
SELECT DISTINCT t2.RoleName,t2.Description,v1.UserName FROM
(SELECT * FROM dbo.Users WHERE UserName=@UserName) v1
JOIN dbo.PolicyUserRole t1 ON v1.UserID = t1.UserID
JOIN dbo.Roles t2 ON t1.RoleID=t2.RoleID ORDER BY t2.RoleName

So it is simple for you to create a new report with the dataset with the
above T-SQL statement. You can set the parameter @UserName to the
expression "=User!UserID" under the Parameters tab on your dataset editor
window.

Hope this helps. If you have any other questions or concerns, please feel
free to let me know.

Best regards,
Charles Wang
Microsoft Online Community Support
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