Added query.md.

query.md

+# Adding more data
+
+Run this query on the MariaDB server of Home Assistant:
+
+```sql
+SELECT metadata_id, state,from_unixtime(last_updated_ts) as datetime FROM `states` where metadata_id in (select metadata_id from states_meta where entity_id = 'sensor.co2_woonkamer_co2' or entity_id = 'binary_sensor.woonkamer_raam') and last_updated_ts is not null and state != 'unknown' and state !='unavailable' and from_unixtime(last_updated_ts) > '2024-05-14T14:28:58' order by datetime;
+```
+Don't forget to modify the date!  
+Export it all as CSV, and place it in the `input` folder.
\ No newline at end of file