``<function> WITHIN GROUP (ORDER BY <criteria>)``, using the
method :class:`.FunctionElement.within_group`.  A series of common
set-aggregate functions with return types derived from the set have
been added. This includes functions like :class:`.percentile_cont`,
:class:`.dense_rank` and others.
fixes #1370
- make sure we use func.name for all _literal_as_binds in functions.py
so we get consistent naming behavior for parameters.

such as :meth:`.Query.union` now handle the case where the embedded
SELECT statements need to be parenthesized due to the fact that they
include LIMIT, OFFSET and/or ORDER BY.   These queries **do not work
on SQLite**, and will fail on that backend as they did before, but
should now work on all other backends.
fixes #2528

assign the proper result type of Boolean to the result mapping, and
instead would leak column types from within the query into the
result map.  This issue exists in 0.9 and earlier as well, however
has less of an impact in those versions.  In 1.0, due to #918
this becomes a regression in that we now rely upon the result mapping
to be very accurate, else we can assign result-type processors to
the wrong column.   In all versions, this issue also has the effect
that a simple EXISTS will not apply the Boolean type handler, leading
to simple 1/0 values for backends without native boolean instead of
True/False.   The fix includes that an EXISTS columns argument
will be anon-labeled like other column expressions; a similar fix is
implemented for pure-boolean expressions like ``not_(True())``.
fixes #3372

the sql package would fail to ``__repr__()`` successfully,
due to a missing ``description`` attribute that would then invoke
a recursion overflow when an internal AttributeError would then
re-invoke ``__repr__()``.
fixes #3195

we're now using; rework them fully so that their behavioral contract
is consistent regarding adapter.traverse() vs. adapter.columns[],
add a full suite of tests including advanced wrapping scenarios
previously only covered by test/orm/test_froms.py and
test/orm/inheritance/test_relationships.py
- identify several cases where label._order_by_label_clause would be
corrupted, e.g. due to adaption or annotation separately
- add full tests for #3148

- apply autopep8 + manual fixes to most of test/sql/

due to repeats would not correctly be rewritten in subqueries.
This would affect SELECT queries with any kind of subquery + join.
fixes #3057

Found using: https://github.com/intgr/topy

there are multiple, equivalent foreign keys