DB.Select("user.*,role.name role_name").Joins("join user_role on user.id=user_role.user_id").Joins("join role on user_role.role_id=role.id").Order("user.id desc").Find(&users)
DB.Select("user.*,role.name role_name").Joins("left join user_role on user.id=user_role.user_id").Joins("left join role on user_role.role_id=role.id").Order("user.id desc").Find(&users)