Python sqlalchemy 模块，nullsfirst() 实例源码

我们从Python开源项目中，提取了以下50个代码示例，用于说明如何使用sqlalchemy.nullsfirst()。

项目：Flask_Blog 作者：sugarguo | 项目源码 | 文件源码

def _create_nullsfirst(cls, column):
        """Produce the ``NULLS FIRST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullsfirst` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullsfirst

            stmt = select([users_table]).\\
                        order_by(nullsfirst(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS FIRST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullsfirst` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullsfirst`, rather than as its standalone
        function version, as in::

            stmt = (select([users_table]).
                    order_by(users_table.c.name.desc().nullsfirst())
                    )

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.nullsfirst_op,
            wraps_column_expression=False)

项目：Flask_Blog 作者：sugarguo | 项目源码 | 文件源码

def _create_nullslast(cls, column):
        """Produce the ``NULLS LAST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullslast` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullslast

            stmt = select([users_table]).\\
                        order_by(nullslast(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS LAST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullslast` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullslast`, rather than as its standalone
        function version, as in::

            stmt = select([users_table]).\\
                        order_by(users_table.c.name.desc().nullslast())

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullsfirst`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.nullslast_op,
            wraps_column_expression=False)

项目：Flask_Blog 作者：sugarguo | 项目源码 | 文件源码

def _create_desc(cls, column):
        """Produce a descending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import desc

            stmt = select([users_table]).order_by(desc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name DESC

        The :func:`.desc` function is a standalone version of the
        :meth:`.ColumnElement.desc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.desc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.desc` operation.

        .. seealso::

            :func:`.asc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.desc_op,
            wraps_column_expression=False)

项目：Flask_Blog 作者：sugarguo | 项目源码 | 文件源码

def _create_asc(cls, column):
        """Produce an ascending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import asc
            stmt = select([users_table]).order_by(asc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name ASC

        The :func:`.asc` function is a standalone version of the
        :meth:`.ColumnElement.asc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.asc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.asc` operation.

        .. seealso::

            :func:`.desc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.asc_op,
            wraps_column_expression=False)

项目：QXSConsolas 作者：qxsch | 项目源码 | 文件源码

def _create_nullsfirst(cls, column):
        """Produce the ``NULLS FIRST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullsfirst` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullsfirst

            stmt = select([users_table]).\\
                        order_by(nullsfirst(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS FIRST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullsfirst` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullsfirst`, rather than as its standalone
        function version, as in::

            stmt = (select([users_table]).
                    order_by(users_table.c.name.desc().nullsfirst())
                    )

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.nullsfirst_op,
            wraps_column_expression=False)

项目：QXSConsolas 作者：qxsch | 项目源码 | 文件源码

def _create_nullslast(cls, column):
        """Produce the ``NULLS LAST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullslast` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullslast

            stmt = select([users_table]).\\
                        order_by(nullslast(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS LAST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullslast` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullslast`, rather than as its standalone
        function version, as in::

            stmt = select([users_table]).\\
                        order_by(users_table.c.name.desc().nullslast())

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullsfirst`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.nullslast_op,
            wraps_column_expression=False)

项目：QXSConsolas 作者：qxsch | 项目源码 | 文件源码

def _create_desc(cls, column):
        """Produce a descending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import desc

            stmt = select([users_table]).order_by(desc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name DESC

        The :func:`.desc` function is a standalone version of the
        :meth:`.ColumnElement.desc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.desc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.desc` operation.

        .. seealso::

            :func:`.asc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.desc_op,
            wraps_column_expression=False)

项目：QXSConsolas 作者：qxsch | 项目源码 | 文件源码

def _create_asc(cls, column):
        """Produce an ascending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import asc
            stmt = select([users_table]).order_by(asc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name ASC

        The :func:`.asc` function is a standalone version of the
        :meth:`.ColumnElement.asc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.asc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.asc` operation.

        .. seealso::

            :func:`.desc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.asc_op,
            wraps_column_expression=False)

项目：flasky 作者：RoseOu | 项目源码 | 文件源码

def _create_nullsfirst(cls, column):
        """Produce the ``NULLS FIRST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullsfirst` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullsfirst

            stmt = select([users_table]).\\
                        order_by(nullsfirst(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS FIRST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullsfirst` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullsfirst`, rather than as its standalone
        function version, as in::

            stmt = (select([users_table]).
                    order_by(users_table.c.name.desc().nullsfirst())
                    )

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_text(column), modifier=operators.nullsfirst_op)

项目：flasky 作者：RoseOu | 项目源码 | 文件源码

def _create_nullslast(cls, column):
        """Produce the ``NULLS LAST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullslast` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullslast

            stmt = select([users_table]).\\
                        order_by(nullslast(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS LAST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullslast` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullslast`, rather than as its standalone
        function version, as in::

            stmt = select([users_table]).\\
                        order_by(users_table.c.name.desc().nullslast())

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullsfirst`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_text(column), modifier=operators.nullslast_op)

项目：flasky 作者：RoseOu | 项目源码 | 文件源码

def _create_desc(cls, column):
        """Produce a descending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import desc

            stmt = select([users_table]).order_by(desc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name DESC

        The :func:`.desc` function is a standalone version of the
        :meth:`.ColumnElement.desc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.desc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.desc` operation.

        .. seealso::

            :func:`.asc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_text(column), modifier=operators.desc_op)

项目：flasky 作者：RoseOu | 项目源码 | 文件源码

def _create_asc(cls, column):
        """Produce an ascending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import asc
            stmt = select([users_table]).order_by(asc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name ASC

        The :func:`.asc` function is a standalone version of the
        :meth:`.ColumnElement.asc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.asc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.asc` operation.

        .. seealso::

            :func:`.desc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_text(column), modifier=operators.asc_op)

项目：oa_qian 作者：sunqb | 项目源码 | 文件源码

def _create_nullsfirst(cls, column):
        """Produce the ``NULLS FIRST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullsfirst` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullsfirst

            stmt = select([users_table]).\\
                        order_by(nullsfirst(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS FIRST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullsfirst` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullsfirst`, rather than as its standalone
        function version, as in::

            stmt = (select([users_table]).
                    order_by(users_table.c.name.desc().nullsfirst())
                    )

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_text(column), modifier=operators.nullsfirst_op)

项目：oa_qian 作者：sunqb | 项目源码 | 文件源码

def _create_nullslast(cls, column):
        """Produce the ``NULLS LAST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullslast` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullslast

            stmt = select([users_table]).\\
                        order_by(nullslast(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS LAST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullslast` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullslast`, rather than as its standalone
        function version, as in::

            stmt = select([users_table]).\\
                        order_by(users_table.c.name.desc().nullslast())

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullsfirst`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_text(column), modifier=operators.nullslast_op)

项目：oa_qian 作者：sunqb | 项目源码 | 文件源码

def _create_desc(cls, column):
        """Produce a descending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import desc

            stmt = select([users_table]).order_by(desc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name DESC

        The :func:`.desc` function is a standalone version of the
        :meth:`.ColumnElement.desc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.desc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.desc` operation.

        .. seealso::

            :func:`.asc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_text(column), modifier=operators.desc_op)

项目：oa_qian 作者：sunqb | 项目源码 | 文件源码

def _create_asc(cls, column):
        """Produce an ascending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import asc
            stmt = select([users_table]).order_by(asc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name ASC

        The :func:`.asc` function is a standalone version of the
        :meth:`.ColumnElement.asc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.asc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.asc` operation.

        .. seealso::

            :func:`.desc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_text(column), modifier=operators.asc_op)

项目：chihu 作者：yelongyu | 项目源码 | 文件源码

def _create_nullsfirst(cls, column):
        """Produce the ``NULLS FIRST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullsfirst` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullsfirst

            stmt = select([users_table]).\\
                        order_by(nullsfirst(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS FIRST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullsfirst` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullsfirst`, rather than as its standalone
        function version, as in::

            stmt = (select([users_table]).
                    order_by(users_table.c.name.desc().nullsfirst())
                    )

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.nullsfirst_op,
            wraps_column_expression=False)

项目：chihu 作者：yelongyu | 项目源码 | 文件源码

def _create_nullslast(cls, column):
        """Produce the ``NULLS LAST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullslast` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullslast

            stmt = select([users_table]).\\
                        order_by(nullslast(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS LAST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullslast` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullslast`, rather than as its standalone
        function version, as in::

            stmt = select([users_table]).\\
                        order_by(users_table.c.name.desc().nullslast())

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullsfirst`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.nullslast_op,
            wraps_column_expression=False)

项目：chihu 作者：yelongyu | 项目源码 | 文件源码

def _create_desc(cls, column):
        """Produce a descending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import desc

            stmt = select([users_table]).order_by(desc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name DESC

        The :func:`.desc` function is a standalone version of the
        :meth:`.ColumnElement.desc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.desc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.desc` operation.

        .. seealso::

            :func:`.asc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.desc_op,
            wraps_column_expression=False)

项目：chihu 作者：yelongyu | 项目源码 | 文件源码

def _create_asc(cls, column):
        """Produce an ascending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import asc
            stmt = select([users_table]).order_by(asc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name ASC

        The :func:`.asc` function is a standalone version of the
        :meth:`.ColumnElement.asc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.asc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.asc` operation.

        .. seealso::

            :func:`.desc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.asc_op,
            wraps_column_expression=False)

项目：ShelbySearch 作者：Agentscreech | 项目源码 | 文件源码

def _create_nullsfirst(cls, column):
        """Produce the ``NULLS FIRST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullsfirst` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullsfirst

            stmt = select([users_table]).\
                        order_by(nullsfirst(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS FIRST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullsfirst` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullsfirst`, rather than as its standalone
        function version, as in::

            stmt = (select([users_table]).
                    order_by(users_table.c.name.desc().nullsfirst())
                    )

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.nullsfirst_op,
            wraps_column_expression=False)

项目：ShelbySearch 作者：Agentscreech | 项目源码 | 文件源码

def _create_nullslast(cls, column):
        """Produce the ``NULLS LAST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullslast` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullslast

            stmt = select([users_table]).\
                        order_by(nullslast(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS LAST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullslast` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullslast`, rather than as its standalone
        function version, as in::

            stmt = select([users_table]).\
                        order_by(users_table.c.name.desc().nullslast())

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullsfirst`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.nullslast_op,
            wraps_column_expression=False)

项目：ShelbySearch 作者：Agentscreech | 项目源码 | 文件源码

def _create_desc(cls, column):
        """Produce a descending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import desc

            stmt = select([users_table]).order_by(desc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name DESC

        The :func:`.desc` function is a standalone version of the
        :meth:`.ColumnElement.desc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.desc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.desc` operation.

        .. seealso::

            :func:`.asc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.desc_op,
            wraps_column_expression=False)

项目：ShelbySearch 作者：Agentscreech | 项目源码 | 文件源码

def _create_asc(cls, column):
        """Produce an ascending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import asc
            stmt = select([users_table]).order_by(asc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name ASC

        The :func:`.asc` function is a standalone version of the
        :meth:`.ColumnElement.asc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.asc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.asc` operation.

        .. seealso::

            :func:`.desc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.asc_op,
            wraps_column_expression=False)

项目：Price-Comparator 作者：Thejas-1 | 项目源码 | 文件源码

def _create_nullsfirst(cls, column):
        """Produce the ``NULLS FIRST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullsfirst` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullsfirst

            stmt = select([users_table]).\\
                        order_by(nullsfirst(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS FIRST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullsfirst` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullsfirst`, rather than as its standalone
        function version, as in::

            stmt = (select([users_table]).
                    order_by(users_table.c.name.desc().nullsfirst())
                    )

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.nullsfirst_op,
            wraps_column_expression=False)

项目：Price-Comparator 作者：Thejas-1 | 项目源码 | 文件源码

def _create_nullslast(cls, column):
        """Produce the ``NULLS LAST`` modifier for an ``ORDER BY`` expression.

        :func:`.nullslast` is intended to modify the expression produced
        by :func:`.asc` or :func:`.desc`, and indicates how NULL values
        should be handled when they are encountered during ordering::


            from sqlalchemy import desc, nullslast

            stmt = select([users_table]).\\
                        order_by(nullslast(desc(users_table.c.name)))

        The SQL expression from the above would resemble::

            SELECT id, name FROM user ORDER BY name DESC NULLS LAST

        Like :func:`.asc` and :func:`.desc`, :func:`.nullslast` is typically
        invoked from the column expression itself using
        :meth:`.ColumnElement.nullslast`, rather than as its standalone
        function version, as in::

            stmt = select([users_table]).\\
                        order_by(users_table.c.name.desc().nullslast())

        .. seealso::

            :func:`.asc`

            :func:`.desc`

            :func:`.nullsfirst`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.nullslast_op,
            wraps_column_expression=False)

项目：Price-Comparator 作者：Thejas-1 | 项目源码 | 文件源码

def _create_desc(cls, column):
        """Produce a descending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import desc

            stmt = select([users_table]).order_by(desc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name DESC

        The :func:`.desc` function is a standalone version of the
        :meth:`.ColumnElement.desc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.desc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.desc` operation.

        .. seealso::

            :func:`.asc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.desc_op,
            wraps_column_expression=False)

项目：Price-Comparator 作者：Thejas-1 | 项目源码 | 文件源码

def _create_asc(cls, column):
        """Produce an ascending ``ORDER BY`` clause element.

        e.g.::

            from sqlalchemy import asc
            stmt = select([users_table]).order_by(asc(users_table.c.name))

        will produce SQL as::

            SELECT id, name FROM user ORDER BY name ASC

        The :func:`.asc` function is a standalone version of the
        :meth:`.ColumnElement.asc` method available on all SQL expressions,
        e.g.::


            stmt = select([users_table]).order_by(users_table.c.name.asc())

        :param column: A :class:`.ColumnElement` (e.g. scalar SQL expression)
         with which to apply the :func:`.asc` operation.

        .. seealso::

            :func:`.desc`

            :func:`.nullsfirst`

            :func:`.nullslast`

            :meth:`.Select.order_by`

        """
        return UnaryExpression(
            _literal_as_label_reference(column),
            modifier=operators.asc_op,
            wraps_column_expression=False)