Perhaps a “fake table” (e.g. a view) that is the result of two tables being joined but presents itself as a normal table with the expected columns? That would be a very declarative way of querying joined tables, but yeah, you’d still have to create the views or have some means of declaring the appropriate relationships between tables. ORMs sort of let you do this, like in Django where you declare that a User has many Permissions and the ORM knows how to generate that JOIN query for you.
I'm just saying they are not declarative since you have to
explicitly describe how each table is joined to the next, the operation goes beyond the query itself.
I think we have different definitions of "declarative", since I consider SQL's join syntax to be pretty darn declarative. You're declaring the relationship between two tables. You're not telling the database how to spool through each table and match up values; you're just telling it which values need to match up by which constraints.
