cakephp virtual fields with subquery and if - mysql

Question

I have a Category table with a name field.
I want to be able to overwrite that name using a PartnerCategory Table and join it.
So usually I would get the Category like this:
$options = array(
'contain' => array('PartnerCategory'),
'conditions' => array(
'Category.slug' => $slug,
'Category.status' => true,
)
);
$category = $this->Category->find('first', $options);
And then check, if ParentCategory.name is not empty and replace the Category.name with it.
Overwriting the name with php is tedious so I checked virtual fields.
I can overwrite the Category.name using this:
$this->virtualFields = array(
'name' => 'SELECT name FROM app_partner_categories WHERE category_id = 1 AND partner_id = 60'
);
But if the name in the PartnerCategory table is empty or no mathes are found, the Category.name would be null.
How can I overwrite Category.name only if PartnerCategory.name is found?

Answer 1

Not sure but this could be a possible solution:
$joins = array(array('table' => 'app_partner_categories',
'alias' => 'PartnerCategory',
'type' => 'INNER',
'conditions' => array(
'PartnerCategory.category_id = Category.id'
)
)
);
$options = array(
'fields' => array('IF(PartnerCategory.name IS NULL or PartnerCategory.name = "", Category.name, PartnerCategory.name) as overwritten_name'),
'joins' => $joins,
'conditions' => array(
'Category.slug' => $slug,
'Category.status' => true,
)
);
$category = $this->Category->find('first', $options);