command, the query will use the two fields &quot; surname &quot; and &quot; city &quot; and return the query result &quot; Smith in Chicago &quot; once and &quot; Smith in London &quot; once.
命令查询 &quot; last name &quot; 和 &quot; city &quot; 两个字段后，查询结果中将返回一条 &quot; Smith in Chicago &quot; 和一条 &quot; Smith in London &quot; 。