sorting in clistview using fields from a related table

Hi all… I am trying sorting in clist view… which works perfectly fine for me with the sorting attributes from the

same table…noe i wamt to know if its possible to sort based on the fields from a related table…

for eg…

<?php $this->widget('zii.widgets.CListView', array(

	'dataProvider'=>$dataProvider,

	'itemView'=>'_viewnew',

	'sortableAttributes'=>array(

        'Date_Of_Joining'

		

		),

)); ?>

works fine…

but i wish to sort from another table field like this…

<?php $this->widget('zii.widgets.CListView', array(

	'dataProvider'=>$dataProvider,

	'itemView'=>'_viewnew',

	'sortableAttributes'=>array(

        'relation_name.Date_Of_Joining'

		

		),

)); ?>

but it does not work… any idea why?

search and read wiki/tutorials…

Searching and sorting by related model in CGridView

you have to provide sorting information for those fields in *DataProvider (you will find examples in tutorial).