old_contents: # Licensed to the Apache Software Foundation (ASF) under one
  # or more contributor license agreements.  See the NOTICE file
  # distributed with this work for additional information
  # regarding copyright ownership.  The ASF licenses this file
  # to you under the Apache License, Version 2.0 (the
  # "License"); you may not use this file except in compliance
  # with the License.  You may obtain a copy of the License at
  #
  #   http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing,
  # software distributed under the License is distributed on an
  # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  # KIND, either express or implied.  See the License for the
  # specific language governing permissions and limitations
  # under the License.
  # pylint: disable=C,R,W
  from superset.db_engine_specs.base import BaseEngineSpec
  
  
  class DruidEngineSpec(BaseEngineSpec):
      """Engine spec for Druid.io"""
  
      engine = "druid"
      inner_joins = False
      allows_subquery = False
  
      time_grain_functions = {
          None: "{col}",
          "PT1S": "FLOOR({col} TO SECOND)",
          "PT1M": "FLOOR({col} TO MINUTE)",
          "PT1H": "FLOOR({col} TO HOUR)",
          "P1D": "FLOOR({col} TO DAY)",
          "P1W": "FLOOR({col} TO WEEK)",
          "P1M": "FLOOR({col} TO MONTH)",
          "P0.25Y": "FLOOR({col} TO QUARTER)",
          "P1Y": "FLOOR({col} TO YEAR)",
      }
  
      @classmethod
      def alter_new_orm_column(cls, orm_col):
          if orm_col.column_name == "__time":
              orm_col.is_dttm = True
  
new_contents: # Licensed to the Apache Software Foundation (ASF) under one
  # or more contributor license agreements.  See the NOTICE file
  # distributed with this work for additional information
  # regarding copyright ownership.  The ASF licenses this file
  # to you under the Apache License, Version 2.0 (the
  # "License"); you may not use this file except in compliance
  # with the License.  You may obtain a copy of the License at
  #
  #   http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing,
  # software distributed under the License is distributed on an
  # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  # KIND, either express or implied.  See the License for the
  # specific language governing permissions and limitations
  # under the License.
  # pylint: disable=C,R,W
  from superset.db_engine_specs.base import BaseEngineSpec
  
  
  class DruidEngineSpec(BaseEngineSpec):
      """Engine spec for Druid.io"""
  
      engine = "druid"
      inner_joins = False
      allows_subquery = True
  
      time_grain_functions = {
          None: "{col}",
          "PT1S": "FLOOR({col} TO SECOND)",
          "PT1M": "FLOOR({col} TO MINUTE)",
          "PT1H": "FLOOR({col} TO HOUR)",
          "P1D": "FLOOR({col} TO DAY)",
          "P1W": "FLOOR({col} TO WEEK)",
          "P1M": "FLOOR({col} TO MONTH)",
          "P0.25Y": "FLOOR({col} TO QUARTER)",
          "P1Y": "FLOOR({col} TO YEAR)",
      }
  
      @classmethod
      def alter_new_orm_column(cls, orm_col):
          if orm_col.column_name == "__time":
              orm_col.is_dttm = True
  
subject: set allows_subquery to True (#7863)