CREATE TABLE foo (doc JSON);

done. If that's really what you want.

For every bit of JSON that comes in?

No

And then having to figure out what all the fields are after the fact?

No

That's why noSQL exists

What is the thin noSQL brings to the table which a relational system doesn't have? (Except that writing a depth search in a JSON document in SQL is a bit more cumbersome, but if that is a concern that can be wrapped in a data access library to generate the SQL)

I think I've explained that above - it's not having to be rigidly tied to a schema :)

Not that my "schema" is really rigid ... just a little more convoluted syntax than "createCollection" but underneath quite similar.