在 MYSQL 中实现动态数据透视答案

【问题标题】：Implement Dynamic pivot in MYSQL在 MYSQL 中实现动态数据透视
【发布时间】：2021-09-28 03:12:29
【问题描述】：

我写了一个mysql查询

SELECT id,GROUP_CONCAT(answer.text) as answer,question.question_name as question
FROM user_answers
inner join answer on user_answers.answer_id=answer.answer_id
inner join question on answer.question_id=question.question_id
GROUP BY id,question.question_id

我得到的结果是

但我希望得到答案

如何转置我的数据。 ?

我试过这个查询。但没有得到实际结果。它的重复

SELECT  id,
     GROUP_CONCAT(
         CASE 
             WHEN question.question_name = 'Household'
             THEN answer.text
             ELSE NULL 
         END
     ) AS Household,
     GROUP_CONCAT(
         CASE 
             WHEN question.question_name = 'Dependents' 
             THEN answer.text
             ELSE NULL 
         END
     ) AS Dependents,
     GROUP_CONCAT(
         CASE 
             WHEN question.question_name = 'Generation'
             THEN answer.text
            ELSE NULL 
         END
     ) AS Generation,
     GROUP_CONCAT(
         CASE 
             WHEN question.question_name = 'Gender' 
             THEN answer.text
             ELSE NULL 
         END
     ) AS 'Gender',
     GROUP_CONCAT(
         CASE 
             WHEN question.question_name = 'Race' 
             THEN answer.text
             ELSE NULL 
         END
     ) AS 'Race',
     GROUP_CONCAT(
         CASE 
             WHEN question.question_name = 'FinancialGoals' 
             THEN answer.text
             ELSE NULL 
         END
     ) AS 'FinancialGoals'
FROM user_answers
inner join answer on user_answers.answer_id=answer.answer_id
inner join question on answer.question_id=question.question_id
GROUP BY id,question.question_id,question.question_name

结果是

添加了激进的功能，结果列仍然重复

【问题讨论】：

这能回答你的问题吗？ How can I return pivot table output in MySQL? 或任何其他链接来自：google.com/search?q=pivot+mysql+site%3Astackoverflow.com
嗨@Luuk，我试过了，但我得到了重复的值。我用重复更新了问题
您必须重新阅读我之前发布的链接，并多加注意。（您的 SQL 语句中缺少一个聚合函数（实际上不止一个）。）
还添加了聚合......但输出相同。它的重复
@Luuk 谢谢。 .. :) 我得到了我的问题.. group by 子句中的问题。

标签： mysql sql pivot mysql-workbench dynamic-pivot

【解决方案1】：

我得到了答案。

SELECT  id,
         GROUP_CONCAT(
             CASE 
                 WHEN question.question_name = 'Household'
                 THEN answer.text
                 ELSE NULL 
             END
         ) AS Household,
         GROUP_CONCAT(
             CASE 
                 WHEN question.question_name = 'Dependents' 
                 THEN answer.text
                 ELSE NULL 
             END
         ) AS Dependents,
         GROUP_CONCAT(
             CASE 
                 WHEN question.question_name = 'Generation'
                 THEN answer.text
                ELSE NULL 
             END
         ) AS Generation
       
    FROM user_answers
    inner join answer on user_answers.answer_id=answer.answer_id
    inner join question on answer.question_id=question.question_id
    GROUP BY id

【讨论】：

你也可以查看answers这个包含动态方法的标题，这里不需要重复question_name列的每个案例。