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The hidden requirement is that you need to join on a key, in an ideal world this would be the primary key of the right table and a foreign key in the left table
by contravariant 3y ago
The hidden requirement is that you need to join on a key, in an ideal world this would be the primary key of the right table and a foreign key in the left table.
Of course this requirement isn't ever enforced because the real world isn't kind enough to give strictly modelled data. It would simplify the query language a lot though.