is that possible to order by a field that is related to a custom module in list view ?

I believe the 

'sortable' => false,

or

'sortable' => true,

setting for the field in question in the 

custom/modules/<your module>/clients/base/views/list/list.php 

will control that.

I believe the 

'sortable' => false,

or

'sortable' => true,

setting for the field in question in the 

custom/modules/<your module>/clients/base/views/list/list.php 

will control that.

thank you

I have done a test but it does break  mysql query as the columns is not found. Francesca Shiekh do you think is there of the way to do that?