zoukankan      html  css  js  c++  java
  • SQL行转列

    1.行转列

    1.经典案例:

    新建一个数据表

    create table STUDENT_SCORE
    (
    name VARCHAR2(20),
    subject VARCHAR2(20),
    score NUMBER(4,1)
    )
    insert into student_score (NAME, SUBJECT, SCORE) values ('张三', '语文', 78.0);
    insert into student_score (NAME, SUBJECT, SCORE) values ('张三', '数学', 88.0);
    insert into student_score (NAME, SUBJECT, SCORE) values ('张三', '英语', 98.0);
    insert into student_score (NAME, SUBJECT, SCORE) values ('李四', '语文', 89.0);
    insert into student_score (NAME, SUBJECT, SCORE) values ('李四', '数学', 76.0);
    insert into student_score (NAME, SUBJECT, SCORE) values ('李四', '英语', 90.0);
    insert into student_score (NAME, SUBJECT, SCORE) values ('王五', '语文', 99.0);
    insert into student_score (NAME, SUBJECT, SCORE) values ('王五', '数学', 66.0);
    insert into student_score (NAME, SUBJECT, SCORE) values ('王五', '英语', 91.0);

    得到类似下面的结果:
    姓名 语文 数学 英语
    王五 89 56 89

    select ts.name,

    sum(decode(ts.subject,'语文',ts.score)) "语文",

    sum(decode(ts.subject,'数学',ts.score)) "数学",

    sum(decode(ts.subject,'英语',ts.score)) "英语"

    from test_score ts

    group by ts.name

  • 相关阅读:
    VB6之GDI+加载PNG图片
    VB6之阴影图层
    VB6之截图
    VB6之调整任务栏按钮的位置
    恐怖的ifdown eth0;0
    VB6之WM_COPYDATA
    删除整个链表
    digest 词根 gest
    new和delete
    static, const
  • 原文地址:https://www.cnblogs.com/abcdjava/p/10878793.html
Copyright © 2011-2022 走看看