从同一个表的多行到具有相似标识符的单行

Question

我是 SQL 查询的新手，我正在尝试将多行压缩为具有类似标识符的单行。下面是一个例子：

Table orders:

groupid | question   | answer

|-----------------------------------|

abc000  | First Name | John 

abc000  | Last Name  | Doe

abc000  | City       | Denver

...     | ...        | ...

abc000  | Entry      | Individual

abc000  | Shirt Size | X-Large

abc001  | First Name | Jane

abc001  | Last Name  | Doe

abc001  | City       | Seattle

...     | ...        | ...

abc001  | Entry      | Individual

(No Shirt entry)

我想让它看起来像：

表格确认（期望的输出）：

组ID |姓氏 |名字 |城市 | ... |衬衫尺码

|---------------------------------------------- ------------|

abc000 |能源部 |约翰 |丹佛 | ... |超大

abc001 |能源部 |简 |西雅图 | ... |小

表格确认（实际输出）：

组ID |姓氏 |名字 |城市 | ... |衬衫尺码

|---------------------------------------------- ------------|

abc000 |能源部 |约翰 |丹佛 | ... |

abc000 |能源部 |约翰 |丹佛 | ... |超大

abc001 |能源部 |简 |西雅图 | ... |

查询是：

SELECT DISTINCT om.groupid, om.fid, om.eid, f.subtitle,
        IF(oi.question = 'First Name', oi.answer, '') AS fname,
        IF(oi1.question = 'Last Name', oi1.answer, '') AS lname,
        IF(oi2.question = 'City', oi2.answer, '') AS city,
        IF(oi3.question = 'State', oi3.answer, '') AS state,
        IF(oi4.question = 'Birthdate', oi4.answer, '') AS bday,
        IF(oi5.question = 'Gender', oi5.answer, '') AS gender,
        IF ( (oi6.question LIKE '%fee'), oi6.answer, '') as event,
        IF ( (oi7.question = 'shirt size (unisex cotton)'), oi7.answer, '') as shirt
    FROM ordermeta om
    JOIN orders o ON o.orderid=om.orderid
    LEFT JOIN orderitems oi ON oi.groupid=om.groupid
    LEFT JOIN orderitems oi1 ON oi1.groupid=om.groupid
    LEFT JOIN orderitems oi2 ON oi2.groupid=om.groupid
    LEFT JOIN orderitems oi3 ON oi3.groupid=om.groupid
    LEFT JOIN orderitems oi4 ON oi4.groupid=om.groupid
    LEFT JOIN orderitems oi5 ON oi5.groupid=om.groupid
    LEFT JOIN orderitems oi6 ON oi6.groupid=om.groupid
    LEFT JOIN orderitems oi7 ON oi7.groupid=om.groupid
    WHERE  oi.question = 'First NAME'
        AND oi1.question = 'Last Name'
        AND oi2.question = 'City'
        AND oi3.question = 'State'
        AND oi4.question = 'Birthdate'
        AND oi5.question = 'Gender'
        AND oi6.question LIKE '%fee%'
    ORDER BY lname ASC

如果我删除衬衫尺码，它会完美运行。我已添加：

AND oi7.question = "Shirt Size" 

除了它可能并不总是“衬衫尺码”，而是更喜欢“%衬衫尺码%”并且当没有=衬衫尺码的问题时，我希望它留下一个空或空白空间。使用 AND，它只会给我同样有衬衫问题的结果。 （140 个结果中的 55 个）

当前代码，当 question = "shirt size" 存在时，我得到两个条目（一个为空白，另一个有很好的信息）。所有其他条目都有一个没有信息的条目。 （140 个结果中的 195 个）

我尝试了多种不同的方法，例如 CASE、IF THEN 语句。在我添加衬衫问题之前，它们都做同样的事情。

如果您需要更多信息，请告诉我。谢谢。

我尝试过的其中一种 SE 类型的示例： Combine multiple rows into one row MySQL

Answer 1

我发现有两个问题有“衬衫”。这是创建第二个适合模型的条目，以将第二行留为空白，因为它不适合选择的第二个过滤器。这是我最终不得不写的。

SELECT DISTINCT om.groupid, om.fid, om.eid, f.subtitle,
        IF(oi.question = 'First Name', oi.answer, '') AS fname,
        IF(oi1.question = 'Last Name', oi1.answer, '') AS lname,
        IF(oi2.question = 'City', oi2.answer, '') AS city,
        IF(oi3.question = 'State', oi3.answer, '') AS state,
        IF(oi4.question = 'Birthdate', oi4.answer, '') AS bday,
        IF(oi5.question = 'Gender', oi5.answer, '') AS gender,
        IF ( (oi6.question LIKE '%fee'), oi6.answer, '') as event,
        IF ( (oi7.question IN ('Youth Shirts','Event Shirt','Tech Shirt Size','Series Shirt','Choose Event Shirt(s)','Shirt Size (Included in Entry)','Regular T-Shirt OR Tech Shirt - Select Size/Type','shirt size (unisex cotton)')), oi7.answer, '') as shirt
    FROM ordermeta om
    JOIN orders o ON o.orderid=om.orderid
    LEFT JOIN orderitems oi ON oi.groupid=om.groupid AND oi.question = 'First Name'
    LEFT JOIN orderitems oi1 ON oi1.groupid=om.groupid AND oi1.question = 'Last Name'
    LEFT JOIN orderitems oi2 ON oi2.groupid=om.groupid AND oi2.question = 'City'
    LEFT JOIN orderitems oi3 ON oi3.groupid=om.groupid AND oi3.question = 'State'
    LEFT JOIN orderitems oi4 ON oi4.groupid=om.groupid AND oi4.question = 'Birthdate'
    LEFT JOIN orderitems oi5 ON oi5.groupid=om.groupid AND oi5.question = 'Gender'
    LEFT JOIN orderitems oi6 ON oi6.groupid=om.groupid AND oi6.question LIKE '%fee%'
    LEFT JOIN orderitems oi7 ON oi7.groupid=om.groupid AND oi7.question IN ('Youth Shirts','Event Shirt','Tech Shirt Size','Series Shirt','Choose Event Shirt(s)','Shirt Size (Included in Entry)','Regular T-Shirt OR Tech Shirt - Select Size/Type','shirt size (unisex cotton)')
    LEFT JOIN forms f ON f.fid=om.fid
    WHERE om.status = 1
        AND o.paid = 1
        AND f.fid=$fid
    ORDER BY lname ASC

这是一个非常丑陋的位，因为衬衫尺寸条目是灵活的......需要标准化条目以使查询仅查找 LIKE "shirt size%"

Answer 2

SELECT  om.groupid, 
        om.fid, 
        om.eid, 
        f.subtitle,
        IF(oi.question = 'First Name', oi.answer, '') AS fname,
        IF(oi1.question = 'Last Name', oi1.answer, '') AS lname,
        IF(oi2.question = 'City', oi2.answer, '') AS city,
        IF(oi3.question = 'State', oi3.answer, '') AS state,
        IF(oi4.question = 'Birthdate', oi4.answer, '') AS bday,
        IF(oi5.question = 'Gender', oi5.answer, '') AS gender,
        IF ( (oi6.question LIKE '%fee'), oi6.answer, '') as event,
        IF ( (oi7.question = 'shirt size (unisex cotton)'), oi7.answer, '') as shirt
    FROM ordermeta om
    JOIN orders o ON o.orderid=om.orderid
    LEFT JOIN orderitems oi ON oi.groupid=om.groupid
    WHERE   oi.question IN( 'First NAME','Last Name','City','State','Birthdate','Gender')
        OR oi.question LIKE  '%fee%'
GROUP BY om.groupid, 
        om.fid, 
        om.eid, 
        f.subtitle,
        IF(oi.question = 'First Name', oi.answer, '') AS fname,
        IF(oi1.question = 'Last Name', oi1.answer, '') AS lname,
        IF(oi2.question = 'City', oi2.answer, '') AS city,
        IF(oi3.question = 'State', oi3.answer, '') AS state,
        IF(oi4.question = 'Birthdate', oi4.answer, '') AS bday,
        IF(oi5.question = 'Gender', oi5.answer, '') AS gender,
        IF ( (oi6.question LIKE '%fee'), oi6.answer, '') as event,
        IF ( (oi7.question = 'shirt size (unisex cotton)'), oi7.answer, '') as shirt
    ORDER BY lname ASC