would produce an empty WHERE clause when an empty :func:`.and_()`
or :func:`.or_()` or other blank expression were applied.  This is
now consistent with that of :func:`.select`.
fixes #3045

"SELECT FIRST n ROWS" using a bound parameter (only firebird has both),
combined with column-level subqueries
which also feature "limit" as well as "positional" bound parameters
(e.g. qmark style) would erroneously assign the subquery-level positions
before that of the enclosing SELECT, thus returning parameters which
are out of order. Fixes #3038

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

a no-name :class:`.BindParameter` is received, e.g. via :func:`.sql.literal`
or similar; the "key" of the bind param is used as the key within
.c. rather than the rendered name.  Since these binds have "anonymous"
names in any case, this allows individual bound parameters to
have their own name within a selectable if they are otherwise unlabeled.
fixes #2974

constructs would fail if the bind were constructed with a callable,
rather than a direct value.  This prevented ORM expressions
from being rendered with the "literal_binds" compiler flag.

such as "literal binds" into a CAST expression.
- Fixed bug whereby binary type would fail in some cases
if used with a "test" dialect, such as a DefaultDialect or other
dialect with no DBAPI.
- Fixed bug where "literal binds" wouldn't work with a bound parameter
that's a binary type.  A similar, but different, issue is fixed
in 0.8.

backwards compatibility.  A note about backslashing escapes is added.
Because the Text() construct now supports bind params better, the example
given in the code raises an exception now, so that should cover us.
The exception itself has been enhanced to include the key name of the
bound param.  We're backporting this to 0.8 but 0.8 doesn't have the
text->bind behavior that raises.

have been modified, such that the COLLATE operator is now of lower
precedence than the comparison operators.  This has the effect that
a COLLATE applied to a comparison will not render parenthesis
around the comparison, which is not parsed by backends such as
MSSQL.  The change is backwards incompatible for those setups that
were working around the issue by applying :meth:`.Operators.collate`
to an individual element of the comparison expression,
rather than the comparison expression as a whole. [ticket:2879]

more flexible ways to set up bound parameters and return types;
in particular, a :func:`.text` can now be turned into a full
FROM-object, embeddable in other statements as an alias or CTE
using the new method :meth:`.TextClause.columns`.
[ticket:2877]