Here's an example i have running on a pi with a temperature sensor. All data is received as json messages in mqtt, then stored as is in a postgres table. The view turns it into relational data.

If i just need the messages between certain temperatures i can speed this up by adding an index on the 'temperature' field in json.

    create or replace view bme680_v(ts, message, temperature, humidity, pressure, gas, iaq) as
    SELECT mqtt_raw.created_at                                          AS ts
     , mqtt_raw.message
     , (mqtt_raw.message::jsonb ->> 'temperature'::text)::numeric    AS temperature
     , (mqtt_raw.message::jsonb ->> 'humidity'::text)::numeric       AS humidity
     , (mqtt_raw.message::jsonb ->> 'pressure'::text)::numeric       AS pressure
     , (mqtt_raw.message::jsonb ->> 'gas_resistance'::text)::numeric AS gas
     , (mqtt_raw.message::jsonb ->> 'IAQ'::text)::numeric            AS iaq
    FROM mqtt_raw
    WHERE mqtt_raw.topic::text = 'pi/bme680'::text
    ORDER BY mqtt_raw.created_at DESC;