有很多表的複雜查詢，這可能在一個查詢中？

我有以下數據庫設計的麻煩（爲例子簡化）。它允許人們創建自定義表單，與Google spreadheat表單非常相似。表單生成腳本已完成，包括將答案保存到數據庫。我無法顯示用戶輸入。有很多表的複雜查詢，這可能在一個查詢中？

表形式（各形式是在該表中的行）

form_id | form_name 
1   Contact Form 
2   BBQ sign up Form

表問題（在表格中的問題）

question_id | form_id | question_name  | sorting_order 
1    1   Full Name   1 
2    1   E-mail address  2 
3    1   Subject    3 
4    1   Message    4 
5    2   Your name   1 
6    2   Are you vegetarian? 2 
7    2   Beer or wine?  3

表completed_forms（以組答案一起）

complete_id | form_id | timestamp 
1   1   1339496914 
2   1   1148691493 
3   2   1256235334

表（從用戶到特定問題的答案）

answer_id | complete_id | question_id | answer 1 1 1 Barack Obama 2 1 2 [email protected] 3 1 3 Test message 4 1 4 This is a test. Regards, Barack. 5 2 1 Thomas something 6 2 2 [email protected] 7 2 3 Another message 8 2 4 Hey, it's Thomas. This is my message. 9 3 5 Dirk 10 3 6 No, I love meat 11 3 7 Red wine!

我想顯示是用戶輸入的概述，這是因爲名字和列數相當複雜的不同每形式回答 。例如，我想顯示從接觸形式的用戶輸入（form_id：1）如下：

id | timestamp | Full Name | E-mail Address | Subject | Message 
1 133949... Barack... [email protected] Test... This is a t... 
2 114869... Thomas... [email protected] Anot... Hey, it's T...

而且從form_id 2如下：

id | timestamp | Your name | Are you vegetarian? | Beer or Wine? 
3 125623... Dirk  No, I love meat  Red wine!

是否如果與任何人怎麼可以做到這一點？

非常感謝任何願意花時間照亮這個問題的人！

來源

2012-06-12 dirk

你想要兩個選擇，一個爲每種類型的？ –

基本上，您正在嘗試編寫一個PIVOT，但MySQL本身沒有PIVOT功能，所以您將不得不編寫查詢有點不同。對於此查詢，您將在提問的值的代碼，你可以使用下面的靜態版本：

表1（見SQL Fiddle with Demo）：

select cf.complete_id 
    , cf.ts 
    , Min(CASE WHEN q.question_name = 'Full Name' THEN a.answer END) as 'Full Name' 
    , Min(CASE WHEN q.question_name = 'Email Address' THEN a.answer END) as 'Email Address' 
    , Min(CASE WHEN q.question_name = 'Subject' THEN a.answer END) as 'Subject' 
    , Min(CASE WHEN q.question_name = 'Message' THEN a.answer END) as 'Message' 
from completed_forms cf 
inner join questions q 
    on cf.form_id = q.form_id 
inner join answers a 
    on cf.complete_id = a.complete_id 
    and q.question_id = a.question_id 
where cf.form_id = 1 
group by cf.complete_id

表2（見SQL Fiddle with Demo）：

select cf.complete_id 
    , cf.ts 
    , Min(CASE WHEN q.question_name = 'Your Name' THEN a.answer END) as 'Your Name' 
    , Min(CASE WHEN q.question_name = 'Are you vegetarian?' THEN a.answer END) as 'Are you vegetarian?' 
    , Min(CASE WHEN q.question_name = 'Beer or Wine' THEN a.answer END) as 'Beer or Wine' 
from completed_forms cf 
inner join questions q 
    on cf.form_id = q.form_id 
inner join answers a 
    on cf.complete_id = a.complete_id 
    and q.question_id = a.question_id 
where cf.form_id = 2 
group by cf.complete_id

現在，由於您的問題將改變爲每個窗體，那麼你應該看看自動化Pivot。我建議您查看位於這裏的文章：

http://www.artfulsoftware.com/infotree/queries.php#523

它包含了如何在MySQL中使用樞軸例子。也有在計算器上其他的答案，應該是能夠幫助動態寫這個：

mysql query to dynamically convert row data to columns

MySQL pivot table with dynamic headers based on single column data

來源

2012-06-12 11:44:09 Taryn

這個作品，你是我的英雄！ – dirk