# Null percent metrics

After you [finish **Step 1 (Metric Info)**](https://lightup.gitbook.io/user-guide/configure-data-quality-metrics/..#step-1-metric-info), **Step 2 (Configure Metric)** appears in the main form:

<figure><img src="https://3772145110-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F7hLPjNTyFMw1VTOP6ZnD%2Fuploads%2FFrJSYp3vlr1BrxULYQVI%2Fnew-np-custom-metric.png?alt=media&#x26;token=b4d863ab-805c-4ab5-8a74-b49d1cd1711b" alt="Step 2 (Configure Metric) of metric configuration for a custom &#x22;Null Percent&#x22; metric"><figcaption></figcaption></figure>

1. Under **Custom Metric Info**, choose a datasource, schema, table, and a column that you'll check for nulls. Optionally, to see a data sample from the table, select **View Sample Data**. &#x20;
2. Under **Configure metric**, some fields may be inheriting values from the table. You'll need to enter values for any that are empty. To use your own values for these fields, select **Override Settings** to unlock the fields for editing.  Note that if the table you chose has partitions, Lightup detects them and displays relevant settings for them just below the heritable settings. If you decide instead that the metric should use the table's settings, select **Inherit Settings** to use the current table settings.
3. Optionally, select a **Seasonality** to indicate how to determine valid periods for running the metric's query. If you choose **Auto seasonality**, Lightup calculates the seasonality for you. Select the gear icon to add custom override periods.
4. &#x20;Optionally, to create a WHERE clause select **Add +**. New fields appear under **Where clause** that you can use to specify the necessary condition. To delete a WHERE clause, use the waste bin icon beside it to the right.&#x20;

<figure><img src="https://3772145110-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F7hLPjNTyFMw1VTOP6ZnD%2Fuploads%2F4ebGbembD24I0ATuDxYq%2Fdel-whereclause.png?alt=media&#x26;token=07fd7548-7a95-4ca9-9933-787460cc3e32" alt="Annotated image of WHERE clause in metric configuration "><figcaption></figcaption></figure>

5\.  Add any tags you want for the metric, then in the top right corner select **Next** to proceed to **Step 3 (Preview)**.

### Step 3 (Preview)

<figure><img src="https://3772145110-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F7hLPjNTyFMw1VTOP6ZnD%2Fuploads%2FM0wLZfqFRqPb4hfJgII6%2Fpreview-cnp.png?alt=media&#x26;token=f351fbce-65eb-4e30-8b79-0ac5c46241af" alt="Annotated image of Step 3 (Preview), of the custom null percent metric configuration"><figcaption></figcaption></figure>

1. Select **View sample data** to see a sample set of rows from the data asset. Lightup returns 100 rows of data from the source table, including metadata. Select **Stop Viewing** when you're done.&#x20;
2. Optionally, adjust the date range for the preview. If you adjust the range, you must pick a start date and an end date.
3. Select **Preview** to see a chart of the metric for the date range from the preceding step.

After you're satisfied with the preview, select **Create** at the top right corner. The Explorer tab opens and displays your new metric in the Explorer tree.
