如果列出“节点收藏”中对应的主题,如何书写最有效率的 SQL? - V2EX
V2EX = way to explore
V2EX 是一个关于分享和探索的地方
现在注册
已注册用户请  登录
MySQL 5.5 Community Server
MySQL 5.6 Community Server
Percona Configuration Wizard
XtraBackup 搭建主从复制
Great Sites on MySQL
Percona
MySQL Performance Blog
Severalnines
推荐管理工具
Sequel Pro
phpMyAdmin
推荐书目
MySQL Cookbook
MySQL 相关项目
MariaDB
Drizzle
参考文档
http://mysql-python.sourceforge.net/MySQLdb.html
daijia1123
V2EX    MySQL

如果列出“节点收藏”中对应的主题,如何书写最有效率的 SQL?

  •  
  •   daijia1123 2015-05-11 17:13:24 +08:00 3265 次点击
    这是一个创建于 3836 天前的主题,其中的信息可能已经有所发展或是发生改变。
    当前节点收藏中是列出收藏的节点,点击节点后才能查看相应主题。
    如果想进入后,直接按时间顺序列出收藏节点的相应主题该如何做最有效率?SELECT * FROM Topics WHERE id IN (SELECT id FROM nodes WHERE userid=uid),这种方式感觉效率不会高。
    数据库结构是否也有特别需要注意的地方(除了索引等)?
    3 条回复    2015-05-11 17:31:16 +08:00
    anoymoux
        1
    anoymoux  
       2015-05-11 17:30:20 +08:00   1
    SELECT * FROM Topics t,nodes n WHERE t.id =n.id and n.userid=uid
    anoymoux
        2
    anoymoux  
       2015-05-11 17:30:49 +08:00   1
    SELECT t.* FROM Topics t,nodes n WHERE t.id =n.id and n.userid=uid
    fangjinmin
        3
    fangjinmin  
       2015-05-11 17:31:16 +08:00   1
    设计上没有什么问题。问题是你用了子查询,一般来说不会快。这样会好一些,select * from topics join nodes on (topics.id = nodes.id) where nodes.userid=uid,然后nodes的userid和id都加上索引。
    关于     帮助文档     自助推广系统     博客     API     FAQ     Solana     1216 人在线   最高记录 6679       Select Language
    创意工作者们的社区
    World is powered by solitude
    VERSION: 3.9.8.5 23ms UTC 23:38 PVG 07:38 LAX 15:38 JFK 18:38
    Do have faith in what you're doing.
    ubao msn snddm index pchome yahoo rakuten mypaper meadowduck bidyahoo youbao zxmzxm asda bnvcg cvbfg dfscv mmhjk xxddc yybgb zznbn ccubao uaitu acv GXCV ET GDG YH FG BCVB FJFH CBRE CBC GDG ET54 WRWR RWER WREW WRWER RWER SDG EW SF DSFSF fbbs ubao fhd dfg ewr dg df ewwr ewwr et ruyut utut dfg fgd gdfgt etg dfgt dfgd ert4 gd fgg wr 235 wer3 we vsdf sdf gdf ert xcv sdf rwer hfd dfg cvb rwf afb dfh jgh bmn lgh rty gfds cxv xcv xcs vdas fdf fgd cv sdf tert sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf shasha9178 shasha9178 shasha9178 shasha9178 shasha9178 liflif2 liflif2 liflif2 liflif2 liflif2 liblib3 liblib3 liblib3 liblib3 liblib3 zhazha444 zhazha444 zhazha444 zhazha444 zhazha444 dende5 dende denden denden2 denden21 fenfen9 fenf619 fen619 fenfe9 fe619 sdf sdf sdf sdf sdf zhazh90 zhazh0 zhaa50 zha90 zh590 zho zhoz zhozh zhozho zhozho2 lislis lls95 lili95 lils5 liss9 sdf0ty987 sdft876 sdft9876 sdf09876 sd0t9876 sdf0ty98 sdf0976 sdf0ty986 sdf0ty96 sdf0t76 sdf0876 df0ty98 sf0t876 sd0ty76 sdy76 sdf76 sdf0t76 sdf0ty9 sdf0ty98 sdf0ty987 sdf0ty98 sdf6676 sdf876 sd876 sd876 sdf6 sdf6 sdf9876 sdf0t sdf06 sdf0ty9776 sdf0ty9776 sdf0ty76 sdf8876 sdf0t sd6 sdf06 s688876 sd688 sdf86