Question with influxDB and texte field

Dear all,
First sorry, I’m newbie on HIO, influxDB and Grafana (and don’t speak English very well !!).

My problem : I try to create a dashboard to follow my consumption of electricity.
U used MQTT, influxdb, and Grafana
For graph with consumption, it’s work very well.
I try to add text information in my dashboard.
First step : retrieve information from MQTT:

Config :

sensor:
- platform: mqtt
state_topic: ‘Jeedom/PTEC’
name: ‘PTEC’

it’s work, I can Had badge in the HA Dashboard.
Second step : give the information to influxdb
Config :

influxdb:
username: XXX
password: XXX
max_retries: 3
default_measurement: state
include:
entities:
- sensor.netatmo_ben_house_indoor_humidity
- sensor.netatmo_ben_house_indoor_temperature
- sensor.indexHP
- sensor.indexHC
- sensor.PAPP
- sensor.PTEC

In influxdb, I have a new measurement : State (like other : temperature, humidity, …)
In Fields, I have friendly_name_str and state

When I run the request :
SELECT mean(“state”) AS “mean_state” FROM “home_assistant”.“autogen”.“state” WHERE time > :dashboardTime: AND time < :upperDashboardTime: AND “entity_id”=‘ptec’ GROUP BY time(:interval:) FILL(null)
Ihave No result and error : unsupported mean iterator type: *query.stringInterruptIterrator …

I’m lost please Help me !!