Report for when another agent enters a note

Summary

We are trying to flag/highlight a row on a report that indicates when another agent has logged a note

Content

We are trying add an exception to a report that indicates when the last agent who logged a note is not the agent that is assigned to the incident.  I have tried this formula but it gives me an error:

if(last(threads.acct_id,threads.entered)<>incidents.assgn_acct_id,1,0)

 

The error I received is:

"The report contains the following errors:

Executing view query failed.

You will need to edit the report to resolve these errors."

The background on this request:  When an agent comes into work in the morning (or at anytime), they want to see if any other agent has put any notes on their tickets.