企业网站管理系统视频教程,广州17做网站,做家政建网站,金空间网站我在一个有大约100k记录的表中有这个查询,它运行得很慢(3-4s),当我取出组时它更快(少于0.5s).我很想知道如何解决这个问题#xff1a;SELECT msg.id,msg.thread_id,msg.senderid,msg.recipientid,from_user.username AS from_name,to_user.username AS to_nameFROM msgtable A…我在一个有大约100k记录的表中有这个查询,它运行得很慢(3-4s),当我取出组时它更快(少于0.5s).我很想知道如何解决这个问题SELECT msg.id,msg.thread_id,msg.senderid,msg.recipientid,from_user.username AS from_name,to_user.username AS to_nameFROM msgtable AS msgLEFT JOIN usertable AS from_user ON msg.senderid from_user.idLEFT JOIN usertabe AS to_user ON msg.recipientid to_user.idGROUP BY msg.thread_idORDER BY msg.id descmsgtable在thread_id,id,senderid和recipientid上有索引.解释回报id select_type table type possible_keys key key_len ref rows Extra1 SIMPLE msg ALL NULL NULL NULL NULL 162346 Using temporary; Using filesort1 SIMPLE from_user eq_ref PRIMARY PRIMARY 4 db.msg.senderid 11 SIMPLE to_user eq_ref PRIMARY PRIMARY 4 db.msg.recipientid 1任何想法如何在返回相同结果时加快速度(每个线程有多个消息,我想在此查询中每个线程只返回一条消息).提前致谢.
