【Android开发】& Expected unique result, but count was 2

使用greendao获取数据，如下query.unque。如果当前的记录数大于一条，再使用query.unique则会报如题的报错。

            Query<EntityBuildingPicInfo> query=entityBuildingPicInfoDao.queryBuilder().where(EntityBuildingPicInfoDao.Properties.Buildinginfo_uuid.eq(
                    longID)).build();
            EntityBuildingPicInfo entityBuildingPicInfo=query.unique();