return CompoundSelect(CompoundSelect.INTERSECT_ALL, *selects, **kwargs)
def alias(selectable, alias=None):
- """Return an :class:`Alias` object.
+ """Return an :class:`.Alias` object.
- An :class:`Alias` represents any :class:`FromClause`
+ An :class:`.Alias` represents any :class:`.FromClause`
with an alternate name assigned within SQL, typically using the ``AS``
clause when generated, e.g. ``SELECT * FROM table AS aliasname``.
- Similar functionality is available via the :func:`alias()` method
- available on all :class:`FromClause` subclasses.
-
- selectable
- any :class:`FromClause` subclass, such as a table, select
- statement, etc..
-
- alias
- string name to be assigned as the alias. If ``None``, a
- random name will be generated.
+ Similar functionality is available via the
+ :meth:`~.FromClause.alias` method
+ available on all :class:`.FromClause` subclasses.
+
+ When an :class:`.Alias` is created from a :class:`.Table` object,
+ this has the effect of the table being rendered
+ as ``tablename AS aliasname`` in a SELECT statement.
+
+ For :func:`.select` objects, the effect is that of creating a named
+ subquery, i.e. ``(select ...) AS aliasname``.
+
+ The ``alias`` parameter is optional, and provides the name
+ to use in the rendered SQL. If blank, an "anonymous" name
+ will be deterministically generated at compile time.
+ Deterministic means the name is guaranteed to be unique against
+ other constructs used in the same statement, and will also be the
+ same name for each successive compilation of the same statement
+ object.
+
+ :param selectable: any :class:`.FromClause` subclass,
+ such as a table, select statement, etc.
+
+ :param alias: string name to be assigned as the alias.
+ If ``None``, a name will be deterministically generated
+ at compile time.
+ **Deprecated** - this argument is called ``name`` in
+ 0.7 for consistency with the other aliasing methods.
"""
return Alias(selectable, alias=alias)
return Join(self, right, onclause, True)
def alias(self, name=None):
- """return an alias of this :class:`FromClause`.
-
- For table objects, this has the effect of the table being rendered
- as ``tablename AS aliasname`` in a SELECT statement.
- For select objects, the effect is that of creating a named
- subquery, i.e. ``(select ...) AS aliasname``.
- The :func:`alias()` method is the general way to create
- a "subquery" out of an existing SELECT.
-
- The ``name`` parameter is optional, and if left blank an
- "anonymous" name will be generated at compile time, guaranteed
- to be unique against other anonymous constructs used in the
- same statement.
+ """return an alias of this :class:`.FromClause`.
+
+ This is shorthand for calling::
+
+ from sqlalchemy import alias
+ a = alias(self, name)
+
+ See :func:`~.expression.alias` for details.
"""
__visit_name__ = 'join'
def __init__(self, left, right, onclause=None, isouter=False):
+ """Construct a new :class:`.Join`.
+
+ The usual entrypoint here is the :func:`~.expression.join`
+ function or the :meth:`.FromClause.join` method of any
+ :class:`.FromClause` object.
+
+ """
self.left = _literal_as_text(left)
self.right = _literal_as_text(right).self_group()
def select(self, whereclause=None, fold_equivalents=False, **kwargs):
"""Create a :class:`Select` from this :class:`Join`.
-
+
+ The equivalent long-hand form, given a :class:`.Join` object
+ ``j``, is::
+
+ from sqlalchemy import select
+ j = select([j.left, j.right], **kw).\\
+ where(whereclause).\\
+ select_from(j)
+
:param whereclause: the WHERE criterion that will be sent to
the :func:`select()` function
:param fold_equivalents: based on the join criterion of this
- :class:`Join`, do not include
+ :class:`.Join`, do not include
repeat column names in the column list of the resulting
select, for columns that are calculated to be "equivalent"
based on the join criterion of this :class:`Join`. This will
return self.left.bind or self.right.bind
def alias(self, name=None):
- """Create a :class:`Select` out of this :class:`Join` clause and
- return an :class:`Alias` of it.
-
- The :class:`Select` is not correlating.
+ """return an alias of this :class:`.Join`.
+
+ Used against a :class:`.Join` object,
+ :meth:`~.Join.alias` calls the :meth:`~.Join.select`
+ method first so that a subquery against a
+ :func:`.select` construct is generated.
+ the :func:`~expression.select` construct also has the
+ ``correlate`` flag set to ``False`` and will not
+ auto-correlate inside an enclosing :func:`~expression.select`
+ construct.
+
+ The equivalent long-hand form, given a :class:`.Join` object
+ ``j``, is::
+
+ from sqlalchemy import select, alias
+ j = alias(
+ select([j.left, j.right]).\\
+ select_from(j).\\
+ with_labels(True).\\
+ correlate(False),
+ name
+ )
+ See :func:`~.expression.alias` for further details on
+ aliases.
+
"""
return self.select(use_labels=True, correlate=False).alias(name)
sub-select within a SQL statement using the ``AS`` keyword (or
without the keyword on certain databases such as Oracle).
- This object is constructed from the :func:`alias()` module level
- function as well as the :func:`alias()` method available on all
- :class:`FromClause` subclasses.
+ This object is constructed from the :func:`~.expression.alias` module level
+ function as well as the :meth:`.FromClause.alias` method available on all
+ :class:`.FromClause` subclasses.
"""
projects / thirdparty / sqlalchemy / sqlalchemy.git / commitdiff
