How can I display a taxonomy term's parent ID in Views?
Thanks Clive! Yes - I just found the solution. I took the following steps:


Under "Relationships" add "Parent term" and untick "Require relationship"
Under "Fields" add "Taxonomy term: Term ID" and under that select from the "Relationship" pulldown "Parent"


Since the relationship is not required, it will correctly show both top-level terms and all children term. Top-level terms has parent ID of 0.