Method scalar

lib/sqlalchemy/orm/query.py:2817–2847

Return the first element of the first result or None if no rows present. If multiple rows are returned, raises :class:`_exc.MultipleResultsFound`. >>> session.query(Item).scalar() >>> session.query(Item.id).scalar() 1 >>> ses

(self)

        return self._iter().one()  # type: ignore

    def scalar(self) -> Any:
        """Return the first element of the first result or None
        if no rows present.  If multiple rows are returned,
        raises :class:`_exc.MultipleResultsFound`.

          >>> session.query(Item).scalar()
          <Item>
          >>> session.query(Item.id).scalar()
          1
          >>> session.query(Item.id).filter(Item.id < 0).scalar()
          None
          >>> session.query(Item.id, Item.name).scalar()
          1
          >>> session.query(func.count(Parent.id)).scalar()
          20

        This results in an execution of the underlying query.

        .. seealso::

            :meth:`_engine.Result.scalar` - v2 comparable method.

        """
        # TODO: not sure why we can't use result.scalar() here
        try:
            ret = self.one()
            if not isinstance(ret, collections_abc.Sequence):
                return ret
            return ret[0]
        except sa_exc.NoResultFound:
            return None

    def __iter__(self) -> Iterator[_T]:
        result = self._iter()