# Condition

A condition defines a boolean expression. If this condition is fulfilled (*true*), then a notification is created which eventually then is going to be delivered to the customer.

<figure><img src="https://2791588365-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fkz3AVy8mukfhOsBy0Lvo%2Fuploads%2FKHUDOPuYlexb6YiaG0yu%2Fimage.png?alt=media&#x26;token=c1e97d1b-49d4-462d-a44e-1466f7121138" alt=""><figcaption><p>This condition shall trigger when the predicted power generation for tomorrow is lower then yesterday's power consumption, and car charges only with photovoltaics.</p></figcaption></figure>

The condition can be expressed as a mathematical expression producing a boolean value, which consists of:

* dataset references \
  E.g. `$MyConsumption` refers to the dataset with name *MyConsumption*
* values \
  E.g. number `1000`
* operators \
  E.g. plus operator `+`, or comparison operator `=`
* functions \
  E.g. average function `AVG(...)`, which calculates the average of specified time series

Have a look at [Rule Language](https://doc.moost.io/platform-manual/rules/rule-language) to see the full feature set of the expression language.