NULL field in top

I have custom module with field “date_closed”. I sort by this field and want to show NULL field in top like:

NULL
NULL

23-12-2017
22-12-2017
21-12-2017

In mysql it is look like
SELECT * FROM xxx ORDER BY xxx.date_closed IS NULL DESC, xxx.date_closed DESC

Is it possible to do some change in suitecrm?

Where are you trying this? In a list view, in a subpanel, in a Report?

I’m not sure I know how to help you, even after you answer that question, but I know that’s where we have to begin - then there are ways to override the classes and change what is displayed by SuiteCRM.

In list view

Try Googling for examples on how to override the listview class. Look for both SuiteCRM and SugarCRM (versions up to 6.5).

You can provide your own Display or ListViewPrepare methods.

Stuff like this, but you might find better examples:
https://community.sugarcrm.com/thread/20188

This will help you understand the generic issues when customizing a view class:
https://suitecrm.com/wiki/index.php/Developer_Guide#Views