Module « sqlalchemy »

Fonction distinct - module sqlalchemy

Signature de la fonction distinct

def distinct(expr) 

Description

distinct.__doc__

Produce an column-expression-level unary ``DISTINCT`` clause.

        This applies the ``DISTINCT`` keyword to an individual column
        expression, and is typically contained within an aggregate function,
        as in::

            from sqlalchemy import distinct, func
            stmt = select(func.count(distinct(users_table.c.name)))

        The above would produce an expression resembling::

            SELECT COUNT(DISTINCT name) FROM user

        The :func:`.distinct` function is also available as a column-level
        method, e.g. :meth:`_expression.ColumnElement.distinct`, as in::

            stmt = select(func.count(users_table.c.name.distinct()))

        The :func:`.distinct` operator is different from the
        :meth:`_expression.Select.distinct` method of
        :class:`_expression.Select`,
        which produces a ``SELECT`` statement
        with ``DISTINCT`` applied to the result set as a whole,
        e.g. a ``SELECT DISTINCT`` expression.  See that method for further
        information.

        .. seealso::

            :meth:`_expression.ColumnElement.distinct`

            :meth:`_expression.Select.distinct`

            :data:`.func`