php – 显示选项中的错误答案

数据库表结构:

会话表(又名考试表)

SessionId(auto)  SessionName
137              XULWQ

问题表:

SessionId  QuestionId  OptionId
137        1           5
137        2           2

Option_Table表:

OptionId  OptionType
1         A-C
2         A-D
3         A-E
4         A-F
5         A-G
6         A-H
7         A-I
8         A-J
9         A-K
10        A-L
11        A-M
12        A-N
13        A-O
14        A-P
15        A-Q
16        A-R
17        A-S
18        A-T
19        A-U
20        A-V
21        A-W
22        A-X
23        A-Y
24        A-Z
25        True or False
26        Yes or No

答案表:

   AnswerId(auto) SessionId  QuestionId  Answer
   200            137        1           B
   201            137        1           D
   202            137        2           F
   203            137        2           A
   204            137        2           C

我想创建一个页面,我希望它显示每个问题的错误答案.

我正在考虑通过检索每个问题的选项类型,显示属于选项类型的所有字母答案,然后从字母答案中删除正确答案,以便仅留下不正确的答案.

选项数组:

$option = array();

$option[1]= array(A,B,C);  
$option[2]= array(A,B,C,D);  
$option[3]= array(A,B,C,D,E);  

...

$option[23]= array(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y);
$option[24]= array(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
$option[25]= array(True,False);  
$option[26]= array(Yes,No);  

我的问题是,在本节之后我需要帮助.如何使用mysqli / php和我目前拥有的数据库开始检索此数组后的错误答案?

更新:

下面显示了sql,它显示了每个问题的正确答案:

  SELECT
      q.QuestionContent, 
      o.OptionType, 
      q.NoofAnswers, 
      GROUP_CONCAT(DISTINCT Answer ORDER BY Answer SEPARATOR '') AS Answer, 
      r.ReplyType, 
      q.QuestionMarks
    FROM Question q
    LEFT JOIN Answer an
      ON q.QuestionId = an.QuestionId
    LEFT JOIN Reply r 
      ON q.ReplyId = r.ReplyId 
    LEFT JOIN Option_Table o 
      ON q.OptionId = o.OptionId 
    group by q.QuestionContent

SQL Fiddle with Demo

这将返回结果:

|      QUESTIONCONTENT | OPTIONTYPE | NOOFANSWERS | ANSWER | REPLYTYPE | QUESTIONMARKS |
----------------------------------------------------------------------------------------
| Name these 2 flowers |        A-F |           2 |      C |  Multiple |             5 |
|         What is 2+2? |        A-D |           1 |    ABD |    Single |             5 |

最佳答案 您的问题在于,Option_Table的设计方式,解码OptionType列以找出所有可能的答案需要一些非常重要的外部知识.

(事实上​​,你没有在我的问题中提供足够的信息,以确定如何做到这一点;我可以猜测你向我展示的那些OptionTypes,但我不能确定是否有,或者可能是,其他人.)

用更简单的表替换(或至少扩充)该表会更好,对于每个OptionId,它只列出所有可能的选项,如下所示:

CREATE TABLE Options (
  OptionId INTEGER NOT NULL,
  OptionAnswer CHAR(1) NOT NULL,  -- or whatever type Answer.Answer has 
  PRIMARY KEY (OptionId, OptionAnswer)
);

INSERT INTO Options VALUES
  (1, 'A'), (1, 'B'), (1, 'C'),
  (2, 'A'), (2, 'B'), (2, 'C'), (2, 'D'),
  -- ...
  (25, 'T'), (25, 'F'),
  (26, 'Y'), (16, 'N');

然后,您可以使用以下查询找到每个问题的所有正确和错误答案:

SELECT
  q.QuestionContent, 
  q.NoofAnswers, 
  GROUP_CONCAT(DISTINCT Answer ORDER BY Answer SEPARATOR '') AS RightAnswers, 
  GROUP_CONCAT(DISTINCT
    CASE
      WHEN Answer IS NULL THEN OptionAnswer
      ELSE NULL
    END
    ORDER BY OptionAnswer SEPARATOR '') AS WrongAnswers, 
  r.ReplyType, 
  q.QuestionMarks
FROM Question q
LEFT JOIN Reply r 
  ON q.ReplyId = r.ReplyId 
LEFT JOIN Options o 
  ON q.OptionId = o.OptionId
LEFT JOIN Answer an
  ON q.QuestionId = an.QuestionId AND o.OptionAnswer = an.Answer
GROUP BY q.SessionId, q.QuestionId

这是一个demo of it on SQLize(稍微修改为跳过未包含在示例表中的列).

编辑:另一种解决方案是在PHP中构造错误答案的列表.例如,如果$row是一个对象(如mysqli_fetch_object()所返回的那样),其中包含原始查询中的一行,则可以计算错误的答案,如下所示:

// Do this (preferably) before looping over the rows:
$specialOptionTypes = array(
    'Yes or No' => array( 'Y', 'N' ),
    'True or False' => array( 'T', 'F' ),
);

// Do this for each row:
if ( array_key_exists( $row->OptionType, $specialOptionTypes ) ) {
    $options = $specialOptionTypes[ $row->OptionType ];
} else if ( preg_match( '/^([A-Z])-([A-Z])$/', $row->OptionType, $match ) ) {
    $options = range( $match[1], $match[2] );
} else {
    // issue warning about unrecognized option type
    $options = array();
}
$right = str_split( $row->Answer );  // or explode() on a delimiter, if any
$wrong = array_diff( $options, $right );
$row->WrongAnswers = implode( '', $wrong );  // if you actually want a string

Here’s a demo on ideone.com,基于您的示例查询输出.

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