多个字段建立索引
alter table landmark_traceroute_R1 add index (id,landmarkid,vantagepointid,routerid);
和
alter table landmark_traceroute_R1 add index (landmarkid);
alter table landmark_traceroute_R1 add index (vantagepoint);
alter table landmark_traceroute_R1 add index (routerid);
实现的功能是相同的嘛?