[throwaway127482]

The columns feature seems somewhat dangerous at first glance. What if I wanted different sets of allowed columns for different parts of the query? Would I have to provide the superset of columns supported in both subqueries / tables?

[pgjones]

The `sql_context` feature is meant to protect against SQL injection. I think for your usecase you would need to supply all columns, but you could used nested t-strings included based on whatever logic you need.