Can't get a calculated field from a model

Here is my situation,

I have one model Item that have some attributes including base (base price for the item), and another model ItemPrice that holds the value for the item in a given season (another model)

so, I want to get the price of the items for a particular season:

$criteria = new CDbCriteria(array(



                    'select'=>array('itemPrices.base * 2 as price')                    





the relations of item is as follow:

public function relations()


    return array(

        'itemPrices' => array(self::HAS_MANY, 'ItemPrice', 'item_id', 'joinType'=>'INNER JOIN'),



Note: I added an attribute price in the model Item to hold the calculated value, but always return null.

I digged into the code needed to be able to get this column and I found that the value is not there because when executing the query the alias price is not changes as the other attributes, changing to a generated alias, say t0_c1, results in getting the calculated value in another attribute, but is not what I want.

can anyone help me please ?!

PD: I’m attaching the schema i’m currently using.