This error is coming from your DB it looks like. It looks like you are trying to compare 2 different data types. I would guess that `member_id` is your varchar (character varying) and that id is your bigint
It looks like you are connecting to a postgres DB, all of my postgres DBs appear to use text and citext rather than varchar (both of which join without errors to bigint) so I cannot test your exact case. What version of Tableau are you using? after 10.2 we can use join calculations. there are a few things you can try
1. change which ever field is the varchar (string in Tableau) to "Number (Whole)" and see if it will let you join (or change the number to string, but if your string contains leading 0s the join will not work
3. either of the above should work, but in the event that they do not, you could try a custom SQL statement, you should be able to work with your DBA if you are unfamiliar with the syntax
Hope this helps!