On the fly virtualfield creation

I have a query, for example:
select tablea.id as SID, tablea.name as SNAME, IF(tablec.tablea_id = tablea.id, ‘Selected’,’’) as SELECTION from tablea left join tablec on tablec.tablea_id = tablea.id LEFT join tableb on tableb.id=tableb_tablea.tableb_id

I want to put this in cakephp find with associations