2011-06-06 33 views

回答

0

试着这么做:

User.find(:all, 
      :joins => 'LEFT JOIN flags ON users.flag_id=flags.id', 
      :group => 'users.id', 
      :having => 'flags.id IS NULL') 
+0

这是我结束了对Rails 3:User.joins( 'LEFT JOIN标志ON users.id = flags.flaggable_id AND flags.flaggable_type = “用户”' ).where('flags.id IS NULL') – 2011-06-06 09:53:39