home-assistant.io/source/_components/sensor.sql.md

layout	title	description	date	sidebar	comments	sharing	footer	logo	ha_category	ha_release
page	SQL Sensor	Instructions how to integrate SQL sensors into Home Assistant.	2018-02-03 00:22	true	false	true	true	sql.png	Sensor	0.63

The SQL sensor platform enables you to use values from an SQL database supported by the sqlalchemy library, to populate a sensor state (and attributes). This can be used to present statistics about Home Assistant sensors if used with the recorder component database. It can also be used with an external data source.

To configure this sensor, you need to define the sensor connection variables and a list of queries to your configuration.yaml file. A sensor will be created for each query:

To enable it, add the following lines to your configuration.yaml:

{% raw %}

# Example configuration.yaml entry to monitor hass database size in MySQL
sensor:
  - platform: sql
    db_url: mysql://user:password@localhost/hass
    queries:
      - name: HASS DB size
        query: 'SELECT table_schema "database", Round(Sum(data_length + index_length) / 1024, 1) "value" FROM information_schema.tables WHERE table_schema="hass" GROUP BY table_schema;'
        column: 'value'
        unit_of_measurement: kB

{% endraw %}

{% configuration %} db_url: description: The URL which points to your database. See supported engines. required: false default: "Defaults to the default recorder db_url (not the current db_url of recorder)." type: string queries: description: List of your queries. required: true type: map keys: name: description: The name of the sensor. required: true type: string query: description: An SQL QUERY string, should return 1 result at most. required: true type: string column: description: The field name to select. required: true type: string unit_of_measurement: description: Defines the units of measurement of the sensor, if any. required: false type: string value_template: description: Defines a template to extract a value from the payload. required: false type: template {% endconfiguration %}

{% linkable_title Examples %}

In this section you find some real life examples of how to use this sensor.

{% linkable_title Current state of an entity %}

This example shows the previously recorded state of sensor abc123.

SELECT * FROM states WHERE entity_id = 'sensor.abc123' ORDER BY id DESC LIMIT 2

Note that the SQL sensor state corresponds to the last row of the SQL resultset.

{% linkable_title Previous state of an entity %}

This example only works with binary_sensors:

SELECT * FROM states WHERE entity_id='binary_sensor.xyz789' GROUP BY state ORDER BY last_changed DESC LIMIT 1

{% linkable_title Database size in Postgres %}

- platform: sql
    db_url: postgresql://user:password@host/dbname
    queries:
    - name: db_size
      query: "SELECT (pg_database_size('dsmrreader')/1024/1024) as db_size;"
      column: "db_size"
      unit_of_measurement: MB