How to use the sqlalchemy.select function in SQLAlchemy

def test_as_scalar(self):
        with testing.expect_deprecated(
            r"The SelectBase.as_scalar\(\) method is deprecated and "
            "will be removed in a future release."
        ):
            stmt = select([self.table1.c.myid]).as_scalar()

        is_true(stmt.compare(select([self.table1.c.myid]).scalar_subquery()))

def _test_criterion(self, engine):
        data_table = self.tables.data_table
        result = engine.execute(
            select([data_table.c.data]).where(
                data_table.c.data["k1"].astext == "r3v1"
            )
        ).first()
        eq_(result, ({"k1": "r3v1", "k2": "r3v2"},))

        result = engine.execute(
            select([data_table.c.data]).where(
                data_table.c.data["k1"].astext.cast(String) == "r3v1"
            )
        ).first()
        eq_(result, ({"k1": "r3v1", "k2": "r3v2"},))

"""
        table1 = table("table1", column("x"))
        table2 = table("table2", column("y"))
        a1 = table1.alias()
        s = select([a1.c.x]).select_from(a1.join(table2, a1.c.x == table2.c.y))

        assert_s = select([select([s.subquery()]).subquery()])
        for fn in (
            sql_util._deep_deannotate,
            lambda s: sql_util._deep_annotate(s, {"foo": "bar"}),
            lambda s: visitors.cloned_traverse(s, {}, {}),
            lambda s: visitors.replacement_traverse(s, {}, lambda x: None),
        ):

            sel = fn(select([fn(select([fn(s.subquery())]).subquery())]))
            eq_(str(assert_s), str(sel))

def test_typedec_operator_adapt(self):
        expr = test_table.c.bvalue + "hi"

        assert expr.type.__class__ is MyTypeDec
        assert expr.right.type.__class__ is MyTypeDec

        eq_(
            testing.db.execute(select([expr.label("foo")])).scalar(),
            "BIND_INfooBIND_INhiBIND_OUT",
        )

'builds.id',
        'buildsets.id',
        'changes.changeid',
        'patches.id',
        'sourcestampsets.id',
        'sourcestamps.id',
        'objects.id',
        'users.uid',
    ]

    for col in to_fix:
        tbl_name, col_name = col.split('.')
        tbl = sautils.Table(tbl_name, metadata, autoload=True)
        col = tbl.c[col_name]

        res = migrate_engine.execute(sa.select([sa.func.max(col)]))
        max = res.fetchall()[0][0]

        if max:
            seq_name = "%s_%s_seq" % (tbl_name, col_name)
            r = migrate_engine.execute("SELECT setval('%s', %d)"
                                       % (seq_name, max))
            r.close()

def __init__(self, slavename):
        self.slavename = slavename

        # slave info, including template
        q = sqlalchemy.select(
            [model.slaves, model.tac_templates.c.template],
            whereclause=(model.slaves.c.name == slavename),
            from_obj = [
                model.slaves.outerjoin(
                    model.tac_templates,
                    onclause=(
                        model.slaves.c.custom_tplid == model.tac_templates.c.tplid))])

        slave_row = q.execute().fetchone()
        if not slave_row:
            raise exceptions.NoAllocationError
        self.slaveid = slave_row.slaveid
        self.enabled = slave_row.enabled
        self.slave_basedir = slave_row.basedir

        # bail out early if this slave is not enabled

"""return the new rewards which are given for the achievement level."""

        this_level = DBSession.execute(select([t_rewards.c.id.label("reward_id"),
                                               t_achievements_rewards.c.id,
                                               t_rewards.c.name,
                                               t_achievements_rewards.c.from_level,
                                               t_achievements_rewards.c.value,
                                               t_achievements_rewards.c.value_translation_id],
                                              from_obj=t_rewards.join(t_achievements_rewards))\
                                       .where(and_(or_(t_achievements_rewards.c.from_level <= level,
                                                       t_achievements_rewards.c.from_level == None),
                                                   t_achievements_rewards.c.achievement_id == achievement_id))\
                                       .order_by(t_achievements_rewards.c.from_level))\
                                       .fetchall()

        prev_level = DBSession.execute(select([t_rewards.c.id.label("reward_id"),
                                               t_achievements_rewards.c.id,
                                               t_achievements_rewards.c.value,
                                               t_achievements_rewards.c.value_translation_id],
                                              from_obj=t_rewards.join(t_achievements_rewards))\
                                       .where(and_(or_(t_achievements_rewards.c.from_level <= level-1,
                                                       t_achievements_rewards.c.from_level == None),
                                                   t_achievements_rewards.c.achievement_id == achievement_id))\
                                       .order_by(t_achievements_rewards.c.from_level))\
                                       .fetchall()

        #now compute the diff :-/
        build_hash = lambda x, l: hashlib.md5((str(x["id"])+str(evaluate_string(x["value"], {"level": l}))+str(Translation.trs(x["value_translation_id"], {"level": l}))).encode("UTF-8")).hexdigest()
        prev_hashes = {build_hash(x, level-1) for x in prev_level}
        #this_hashes = {build_hash(x,level) for x in this_level}

        retlist = [x for x in this_level if not build_hash(x, level) in prev_hashes]

def insert_dataset(session, data, tbl):
    '''Batch insert data into the database using PostGIS specific functions.

    :param session: SQLAlchemy Session
    :type session: sqlalchemy.orm.session.Session
    :param data: DataFrame containing value, timestamp, longitude and latitude
    :type data: pandas.core.frame.DataFrame
    :param tbl: Base class representing the database table for the data
    :type tbl: sqlalchemy.ext.declarative.api.DeclarativeMeta
    '''
    values = sqlalchemy.select([sqlalchemy.func.unnest(data.value),
                                sqlalchemy.func.unnest(data.timestamp),
                                sqlalchemy.func.ST_MakePoint(
                                    sqlalchemy.func.unnest(data.longitude),
                                    sqlalchemy.func.unnest(data.latitude))])
    query = sqlalchemy.insert(tbl).from_select(tbl.columns, values)
    session.execute(query)

def _answer_stat(survey_node: AnswerableSurveyNode,
                 allowable_types: set,
                 func: Function) -> object:
    type_constraint = survey_node.the_type_constraint
    if type_constraint not in allowable_types:
        raise InvalidTypeForOperation(
            (type_constraint, func._FunctionGenerator__names[0])
        )
    answer_cls = ANSWER_TYPES[survey_node.the_type_constraint]
    return (
        object_session(survey_node)
        .scalar(
            sa.select([func(answer_cls.main_answer)])
            .select_from(Answer.__table__.join(
                answer_cls.__table__, Answer.id == answer_cls.id
            ))
            .where(Answer.survey_node_id == survey_node.id)
        )

def downgrade(migrate_engine):
    meta = MetaData()
    meta.bind = migrate_engine

    instances = Table('instances', meta, autoload=True)
    volumes = Table('volumes', meta, autoload=True)
    instance_id_column = Column('instance_id', Integer)

    instance_id_column.create(volumes)
    try:
        volumes.update().values(
            instance_id=select(
                [instances.c.id],
                instances.c.uuid == volumes.c.instance_uuid)
                ).execute()
    except Exception:
        instance_id_column.drop()

    fkeys = list(volumes.c.instance_id.foreign_keys)
    if fkeys:
        try:
            fk_name = fkeys[0].constraint.name
            ForeignKeyConstraint(
                columns=[volumes.c.instance_id],
                refcolumns=[instances.c.id],
                name=fk_name).create()

        except Exception: