将行转置为 MYSQL 中的标题 [英] Transpose Rows to Headers in MYSQL

问题描述

我正在尝试转置一个非常基本的输出以用于 Web 应用程序.由于我的优势更多在于 mysql，所以我想在它进入应用程序之前这样做.

I'm trying to transpose a very basic output for use in a web application. As my strengths lie moreso in mysql, I'd like to this before it hits the app.

我目前拥有的是:

date          value
2012-01-01    23
2012-01-02    33
2012-01-03    56
2012-01-04    10

我想要的是:

2012-01-01  2012-01-02  2012-01-03  2012-01-04
23          33          56          10

我的sql是:

SELECT

date,
value
from values
where date >= curdate() - interval 3 day

我已经在网上进行了大量研究，但我想不出一个好的方法来做到这一点.这需要是动态的，因为日期确实每天都在变化.

I've done a ton of research online and I can't figure out a good way to do this. This would need to be dynamic as the dates do change daily.

推荐答案

这是一个动态 sql 来透视记录，

Here's a dynamic sql to pivot records,

SET @sql = NULL;

SELECT  GROUP_CONCAT(DISTINCT
        CONCAT('MAX(CASE WHEN date = ''',
               date,
               ''' THEN Value ELSE NULL END) AS ',
               CONCAT('`', date, '`')
               )) INTO @sql
FROM TableName
// WHERE date >= curdate() - interval 3 day  // add condition here
ORDER BY date;



SET @sql = CONCAT('SELECT ', @sql, ' 
                   FROM TableName');

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

• SQLFiddle 演示

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