Insufficient privileges on an update join

Try using the ISO approved format for an Update statement and see if that works. ISO does not provide for using a Join directly in an Update statement. Rather, you can only use joins via subqueries.

In addition, this may illustrate some problems in your original Update statement if, for example, the subquery used to set approver_id returns more than one row which will obviously cause an exception and you'll need to determine how to find the one and only one supervisor_id that should be set for each row.

Update gs3.request_workflowSet approver_id =   (                    Select gup.supervisor_id                    From gs3.user_role As gur                        Join gsu.user_profile As gup                            On gur.user_id = gup.user_id                    Where gup.user_role_id = gs3.request_workflow.user_role_id                        And gup.supervisor_id != grw.approver_user_id                    )Where auth_status_cd = 'SUBMITTED'                              And Exists  (                Select 1                From gs3.user_role As gur                    Join gsu.user_profile As gup                        On gur.user_id = gup.user_id                Where gup.user_role_id = gs3.request_workflow.user_role_id                    And gup.supervisor_id != grw.approver_user_id                )