Method first

lib/sqlalchemy/orm/query.py:2795–2823

Return the first result of this ``Query`` or None if the result doesn't contain any row. first() applies a limit of one within the generated SQL, so that only one primary entity row is generated on the server side (note this may consist of multiple result rows if joi

(self)

        return self

    def first(self) -> Optional[_T]:
        """Return the first result of this ``Query`` or
        None if the result doesn't contain any row.

        first() applies a limit of one within the generated SQL, so that
        only one primary entity row is generated on the server side
        (note this may consist of multiple result rows if join-loaded
        collections are present).

        Calling :meth:`_query.Query.first`
        results in an execution of the underlying
        query.

        .. seealso::

            :meth:`_query.Query.one`

            :meth:`_query.Query.one_or_none`

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

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

        """
        # replicates limit(1) behavior
        if self._statement is not None:
            return self._iter().first()  # type: ignore
        else:
            return self.limit(1)._iter().first()  # type: ignore

    def one_or_none(self) -> Optional[_T]:
        """Return at most one result or raise an exception.