數(shù)據(jù)庫實(shí)現(xiàn)行列轉(zhuǎn)換(mysql示例)

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數(shù)據(jù)庫實(shí)現(xiàn)行列轉(zhuǎn)換(mysql示例)

數(shù)據(jù)庫實(shí)現(xiàn)行列轉(zhuǎn)換(mysql示例):這篇文章通過sql示例代碼給大家介紹了mysql數(shù)據(jù)庫如何實(shí)現(xiàn)行列轉(zhuǎn)換，下面話不多說，直接來看示例代碼吧。原表：表名 :user ---------------------------------------- name | course | grade -----------------------

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點(diǎn)擊下載本文 文檔為doc格式

導(dǎo)讀數(shù)據(jù)庫實(shí)現(xiàn)行列轉(zhuǎn)換(mysql示例):這篇文章通過sql示例代碼給大家介紹了mysql數(shù)據(jù)庫如何實(shí)現(xiàn)行列轉(zhuǎn)換，下面話不多說，直接來看示例代碼吧。原表：表名 :user ---------------------------------------- name | course | grade -----------------------

這篇文章通過sql示例代碼給大家介紹了mysql數(shù)據(jù)庫如何實(shí)現(xiàn)行列轉(zhuǎn)換，下面話不多說，直接來看示例代碼吧。

原表：

表名 :user
----------------------------------------
name | course | grade
----------------------------------------
zhangsan | Java | 70
----------------------------------------
zhangsan | C++ | 80
----------------------------------------
lisi | java | 90
----------------------------------------
lisi | C# | 60
----------------------------------------

用一條 SQL 語句得到如下形式：

----------------------------------------
name | java | C++ | C#
----------------------------------------
zhangsan | 70 | 80 | null
----------------------------------------
lisi | 90 | null | 60
----------------------------------------

方案一

select name,
sum(case when course='java' then grade end) as java,
sum(case when course='C++' then grade end) as C++,
sum(case when course='C#' then grade end) as C#
from test group by name

方案二

select distinct c.`name` AS name,
(select grade from test where name = c.`name` and course = 'java' )as java,
(select grade from test where name = c.`name` and course = 'C++' )as C++,
(select grade from test where name = c.`name` and course = 'C#' )as C#
from test c

總結(jié)

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數(shù)據(jù)庫實(shí)現(xiàn)行列轉(zhuǎn)換(mysql示例)

推薦度：

點(diǎn)擊下載本文 文檔為doc格式

標(biāo)簽：行列轉(zhuǎn)換數(shù)據(jù)庫 mysql

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數(shù)據(jù)庫實(shí)現(xiàn)行列轉(zhuǎn)換(mysql示例)

數(shù)據(jù)庫實(shí)現(xiàn)行列轉(zhuǎn)換(mysql示例)

數(shù)據(jù)庫實(shí)現(xiàn)行列轉(zhuǎn)換(mysql示例)

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