The CTE construct was missing a _copy_internals() method
which would handle CTE-specific structures including _cte_alias,
_restates during a clone operation.

Change-Id: I9aeac9cd24d8f7ae6b70e52650d61f7c96cb6d7e
Fixes: #3722

Adds ``key_share=True`` for with_for_update().

Co-authored-by: Mike Bayer <mike_mp@zzzcomputing.com>
Change-Id: I74e0c3fcbc023e1dc98a1fa0c7db67b4c3693a31
Pull-request: https://github.com/zzzeek/sqlalchemy/pull/279

This adds `SELECT ... FOR UPDATE SKIP LOCKED`/
`SELECT ... FOR SHARE SKIP LOCKED` rendering.

Change-Id: Id1dc4f1cafc1de23f397a6f73d54ab2c58d5910d
Pull-request: https://bitbucket.org/zzzeek/sqlalchemy/pull-requests/86

for the SQL standard LATERAL keyword, currently only supported
by Postgresql.  fixes #2857

Pull request courtesy Stefan Urbanek.  fixes #1957

INSERT, UPDATE, and DELETE statements to both specify their own
WITH clause, as well as for these statements themselves to be
CTE expressions when they include a RETURNING clause.
fixes #2551

method, and its interaction with result-row processing, now allows
the columns passed to the method to be positionally matched with the
result columns in the statement, rather than matching on name alone.
The advantage to this includes that when linking a textual SQL statement
to an ORM or Core table model, no system of labeling or de-duping of
common column names needs to occur, which also means there's no need
to worry about how label names match to ORM columns and so-forth.  In
addition, the :class:`.ResultProxy` has been further enhanced to
map column and string keys to a row with greater precision in some
cases.  fixes #3501
- reorganize the initialization of ResultMetaData for readability
and complexity; use the name "cursor_description", define the
task of "merging" cursor_description with compiled column information
as its own function, and also define "name extraction" as a separate task.
- fully change the name we use in the "ambiguous column" error to be the
actual name that was ambiguous, modify the C ext also

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