Search restriction on based on a custom created attribute of user

Hi,

I have a requirement in which a product manager (user) is able so view products of a particular brand only, I created a new attribute called brand for itemtype user. The query I've made for this search restriction is:

{brand} IN ({{select {pk} from {BrandLabel} where {code} = (?session.user.brand)}}) where BrandLabel contains the list of brand names.

This query is not working for me.