mysql 二次查询并合并结果集

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This topic created in 2396 days ago, the information mentioned may be changed or developed.

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 replies • 2019-10-15 19:12:10 +08:00

BacGa

Oct 15, 2019

用 name 连表查询就行

TimFire

Oct 15, 2019

现在那么多孩子叫 zixuan 的，重名不考虑的啊？

b821025551b

Oct 15, 2019

你这玩意，重名了咋办

wangyzj

Oct 15, 2019

为啥不 join

zclHIT

Oct 15, 2019

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

Oct 15, 2019

用唯一 id 喽 class 里为了区分重名肯定存了 id

mysql 二次查询并合并结果集

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|

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;