Oracle纵向表转换为横向表写法 假设存在如下纵向表,第一列为id(可能是某个业务数据的id),第二列为类型,第三列为类型对应的值
Oracle纵向表转换为横向表写法
假设存在如下纵向表,第一列为id(可能是某个业务数据的id),第二列为类型,第三列为类型对应的值,如下图:
如上表,存在2,3,4三种类型,其中业务数据ID为1的三种类型都有值,业务数据ID为2的三种类型都有值,业务数据ID为3的只有类型2和3有值,现在要把纵向表横过来显示,可以采用如下代码:
-- =========================================================
-- 纵向表变横向表:
-- 1. 转换类型,类型的值必须是整数,且不等于0,即0没有意义,0可以表示为空
-- =========================================================
SELECT
t.id,
SUM(DECODE(t.code, 2, 2, 0)) "第二项", -- 如果该行类型为2则就是2,其它的都为0
SUM(DECODE(t.code, 3, 3, 0)) "第三项",
SUM(decode(t.code, 4, 4, 0)) "第四项"
FROM ttt t WHERE t.id=1 GROUP BY t.id;
-- =========================================================
-- 纵向表变横向表:
-- 1. 转换类型对应的数据,且数据需要是数值,且0没有意义,,即0可以表示为空
-- =========================================================
SELECT
t.id,
SUM(DECODE(t.code, 2, t.val, 0)) "第二项", -- 如果该行类型为2则显示2类型对应的值DECODE,否则都显示0
SUM(DECODE(t.code, 3, t.val, 0)) "第三项",
SUM(DECODE(t.code, 4, t.val, 0)) "第四项"
FROM ttt t GROUP BY t.id;

This article explores optimizing MySQL memory usage in Docker. It discusses monitoring techniques (Docker stats, Performance Schema, external tools) and configuration strategies. These include Docker memory limits, swapping, and cgroups, alongside

The article discusses using MySQL's ALTER TABLE statement to modify tables, including adding/dropping columns, renaming tables/columns, and changing column data types.

This article addresses MySQL's "unable to open shared library" error. The issue stems from MySQL's inability to locate necessary shared libraries (.so/.dll files). Solutions involve verifying library installation via the system's package m

This article compares installing MySQL on Linux directly versus using Podman containers, with/without phpMyAdmin. It details installation steps for each method, emphasizing Podman's advantages in isolation, portability, and reproducibility, but also

This article provides a comprehensive overview of SQLite, a self-contained, serverless relational database. It details SQLite's advantages (simplicity, portability, ease of use) and disadvantages (concurrency limitations, scalability challenges). C

This guide demonstrates installing and managing multiple MySQL versions on macOS using Homebrew. It emphasizes using Homebrew to isolate installations, preventing conflicts. The article details installation, starting/stopping services, and best pra

Article discusses configuring SSL/TLS encryption for MySQL, including certificate generation and verification. Main issue is using self-signed certificates' security implications.[Character count: 159]

Article discusses popular MySQL GUI tools like MySQL Workbench and phpMyAdmin, comparing their features and suitability for beginners and advanced users.[159 characters]


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

WebStorm Mac version
Useful JavaScript development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

SublimeText3 Chinese version
Chinese version, very easy to use

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

Dreamweaver Mac version
Visual web development tools
