Campus is a field on the person's family group, so I typically write query to get person's primary family and then update the campus property on that group. Not sure if it's the best way, but...

Here's the SQL from that screenshot...
{% sql %}
SELECT TOP 1 G.[Guid]
FROM [PersonAlias] PA
INNER JOIN [GroupMember] GM ON GM.[PersonId] = PA.[PersonId]
INNER JOIN [Group] G ON G.[Id] = GM.[GroupId] AND G.[GroupTypeId] = 10
WHERE PA.[Guid] = '{{ Workflow | Attribute:'Person','RawValue' }}'
ORDER BY ISNULL(GM.[GroupOrder], 99999)
{% endsql %}
{% for item in results %}
{{ item.Guid }}
{% endfor %}