A similar technique is used when applying the unique filter to the outer query, with dot notation used to indicate the field by which results are to be filtered.
在对外部查询应用惟一筛选器时可使用类似的技术，点符号将用于说明筛选结果所依据的字段。
2
By using the for clause in the after-aggregation detail filter on a non-projected data item, the underlying query automatically projects and groups the item as the outer most column of the list.