+def select_sensordata_grouped(sensor_id, sensor_type, begin, end):
+ # determine resolution (interval in seconds for data points)
+ resolution = calc_grouping_resolution(begin, end)
+
+ # Let the database do the grouping. Example in SQL (MySQL):
+ # select to_seconds(datetime) DIV (60*60*24) as interval_id, min(datetime), max(datetime), min(temp), avg(temp), max(temp), count(temp) from openweathermap group by interval_id order by interval_id;
+ query = db.session.query(func.to_seconds(Sensors.timestamp).op('div')(resolution).label('g'),
+ func.from_unixtime(func.avg(func.unix_timestamp(Sensors.timestamp))).label('timestamp'),
+ func.avg(Sensors.value).label('value'),
+ Sensors.sensor_id, Sensors.value_type, Sensors.sensor_name)
+ if sensor_id is not None:
+ query = query.filter(Sensors.sensor_id == sensor_id)
+ if sensor_type is not None:
+ query = query.filter(Sensors.value_type == sensor_type)
+ query = query.filter(Sensors.timestamp >= begin)
+ query = query.filter(Sensors.timestamp <= end)
+ query = query.group_by('g', Sensors.sensor_id, Sensors.value_type, Sensors.sensor_name)
+ return query.all()
+
+
+def select_openweatherdata(cityid, begin, end):