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# where_expression

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`where_expression: [sql expression]`

Filter the tested data using a valid sql expression.

* *Default: None*
* *Relevant tests: All anomaly detection tests*

The `where_expression` is used to filter out the data that you want to test. For example, to only test weekdays for anomalies, you can filter on the day of the week:

```yml theme={null}
where_expression: EXTRACT(DOW FROM timestamp_column) BETWEEN 2 AND 6 
#Test Monday through Friday
```

<RequestExample>
  ```yml test theme={null}
  models:
    - name: this_is_a_model
      data_tests:
        - elementary.volume_anomalies:
            arguments:
              where_expression: "user_name != 'test'"
  ```

  ```yml model theme={null}
  models:
    - name: this_is_a_model
      config:
        elementary:
          where_expression: "loaded_at is not null"
  ```

  ```yml dbt_project.yml theme={null}
  vars:
    where_expression: "loaded_at > '2022-01-01'"
  ```
</RequestExample>