there's a tuple_() operator:
http://www.sqlalchemy.org/docs/core/expression_api.html?highlight=tuple_#sqlalchemy.sql.expression.tuple_
the object returns is _Tuple. if you wanted fancy per-dialect expression
behavior, mmm tricky, you'd need to subclass _Tuple (or write a new object),
SQL-92 defines a row value constructor expression like (1,2,3)
which looks and behaves exactly like a Python tuple, as far as I can
tell. These are implemented correctly in mysql at least, and I believe
PostgreSQL and Oracle as well, although I don't have access to those
systems.
What would be
