Select distinct value

Hi,

I am trying to select distinct value from a table.

$models=Product::model()->findAll(array(
    'select'=>'t.Category',
    'distinct'=>true,
));

Using the above, I get an array of Active Record. What I want is an array of distinct product category. I am aware that I need to do a loop through and build array myself.

Is there a way to just get an array of distinct product category ?

Thank you