mysql 二次查询并合并结果集 - 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
meinjoy
V2EX    MySQL

mysql 二次查询并合并结果集

  •  
  •   meinjoy 2019-10-15 13:33:07 +08:00 7462 次点击
    这是一个创建于 2219 天前的主题,其中的信息可能已经有所发展或是发生改变。

    第一个表 class 中随机获取 5 组数据 SELECT name,age FROM class , (SELECT ((1/COUNT(*))*100) as n FROM class) as x WHERE RAND()<=x.n ORDER BY RAND() LIMIT 5;

    | name | age |

    然后再用 class 表中的值 name 从第二表 score 中查询结果 select * from score where name=name

    math | eng|

    有没有办法合并成一句 sql 语句并把结果合并成

    | name | age | math | eng|

    6 条回复    2019-10-15 19:12:10 +08:00
    BacGa
        1
    BacGa  
       2019-10-15 13:36:02 +08:00
    用 name 连表查询就行
    TimFire
        2
    TimFire  
       2019-10-15 13:53:32 +08:00
    现在那么多孩子叫 zixuan 的,重名不考虑的啊?
    b821025551b
        3
    b821025551b  
       2019-10-15 14:09:44 +08:00
    你这玩意,重名了咋办
    wangyzj
        4
    wangyzj  
       2019-10-15 14:13:21 +08:00
    为啥不 join
    zclHIT     5
    zclHIT  
       2019-10-15 18:27:03 +08:00
    Select c.name, c.age, s.math, s.eng, (select ((1/COUNT(*))*100) as n) as x from class c inner join score on c.name = s.name where rand()<=x.n order by rand() lmiit 5;
    1. 名字不会重复吗?
    2.这个随机的逻辑有点复杂吧
    BacGa
        6
    BacGa  
       2019-10-15 19:12:10 +08:00
    用唯一 id 喽 class 里为了区分重名肯定存了 id
    关于     帮助文档     自助推广系统     博客     API     FAQ     Solana     5251 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 27ms UTC 07:10 PVG 15:10 LAX 23:10 JFK 02:10
    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