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當我按提交按鈕來提交表單時，我的查詢結果中沒有顯示任何記錄。我不知道這是爲什麼。我知道這個查詢是正確的，因爲我之前已經測試過它，但是當我包含WHERE子句時它不起作用，但是我相信這是在根據表單中輸入內容檢索行時正確的代碼。它沒有爲我的查詢結果輸出任何行，這是爲什麼？
另外我想顯示作爲AnswerContent的數組StudentAnswer，但是當我這樣做AnswerContent只顯示每個AnswerId。我如何做到爲每個StudentAnswer顯示？ StudentAnswer與AnswerId相同，因爲無論選擇哪個答案，它都會通過其ID檢索答案並將其存儲在StudentAnswer字段中。請幫忙。
下面是我的代碼：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Exam Q & A</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
<?php
$username="xxx";
$password="xxx";
$database="mobile_app";
mysql_connect('localhost',$username,$password);
@mysql_select_db($database) or die("Unable to select database");
foreach (array('sessionid','questionno','studentid','orderfield') as $varname) {
$$varname = (isset($_POST[$varname])) ? $_POST[$varname] : '';
}
switch ($orderfield) {
case 'orderquestionno':
$orderfield = 'q.QuestionNo';
$ordername = 'Question Number';
break;
case 'orderstudentid':
$orderfield = 'sa.StudentId';
$ordername = 'Student Username';
break;
case 'orderwhole':
$orderfield = 'q.SessionId AND q.QuestionNo';
$ordername = 'Session ID and Question Number';
break;
case 'ordersessionid':
default:
$orderfield = 'q.SessionId';
$ordername = 'Session ID';
break;
}
?>
<h1>MOBILE EXAM QUESTIONS AND ANSWERS SEARCH</h1>
<p><strong>NOTE: </strong>If a search box is left blank, then the form will search for all data under that specific field</p>
<form action="exam_QA.php" method="post" name="sessionform"> <!-- This will post the form to its own page"-->
<p>Session ID: <input type="text" name="sessionid" value="<?php echo $sessionid; ?>" /></p> <!-- Enter Session Id here-->
<p>Question Number: <input type="text" name="questionno" value="<?php echo $questionno; ?>" /></p> <!-- Enter Question Number here-->
<p>Student Username: <input type="text" name="studentid" value="<?php echo $studentid; ?>" /></p> <!-- Enter User Id here-->
<p>Order Results By:
<select name="orderfield">
<option value="ordersessionid"<?php if ($orderfield == 'q.SessionId') echo ' selected="selected"' ?>>Session ID</option>
<option value="orderquestionno"<?php if ($orderfield == 'q.QuestionNo') echo ' selected="selected"' ?>>Question Number</option>
<option value="orderstudentid"<?php if ($orderfield == 'sa.StudentId') echo ' selected="selected"' ?>>Student Username</option>
<option value="orderwhole"<?php if ($orderfield == 'q.SessionId AND q.QuestionNo') echo ' selected="selected"' ?>>Session ID and Question Number</option>
</select>
</p>
<p><input type="submit" value="Submit" name="submit" /></p>
</form>
<?php
if (isset($_POST['submit'])) {
$query = "
SELECT *, a2.AnswerContent as StudentAnswerContent
FROM Question q
INNER JOIN StudentAnswer sa ON q.QuestionId = sa.QuestionId
LEFT JOIN Answer a ON (sa.QuestionId = a.QuestionId AND a2.CorrectAnswer = 1)
LEFT JOIN Answer a2 ON (sa.QuestionId = a2.QuestionId AND a2.AnswerId = sa.StudentAnswer)
WHERE
('".mysql_real_escape_string($sessionid)."' = '' OR q.SessionId = '".mysql_real_escape_string($sessionid)."')
AND
('".mysql_real_escape_string($questionno)."' = '' OR q.QuestionNo = '".mysql_real_escape_string($questionno)."')
AND
('".mysql_real_escape_string($studentid)."' = '' OR sa.StudentId = '".mysql_real_escape_string($studentid)."')
ORDER BY $orderfield ASC";
$num = mysql_num_rows($result = mysql_query($query));
mysql_close();
?>
<p>
Your Search:
<strong>Session ID:</strong> <?php echo (empty($sessionid)) ? "'All Sessions'" : "'$sessionid'"; ?>,
<strong>Question Number:</strong> <?php echo (empty($questionno)) ? "'All Questions'" : "'$questionno'"; ?>,
<strong>Student Username:</strong> <?php echo (empty($studentid)) ? "'All Students'" : "'$studentid'"; ?>,
<strong>Order Results By:</strong> '<?php echo $ordername; ?>'
</p>
<p>Number of Records Shown in Result of the Search: <strong><?php echo $num ?></strong></p>
<table border='1'>
<tr>
<th>Session ID</th>
<th>Question Number</th>
<th>Question</th>
<th>Correct Answer</th>
<th>StudentAnswer</th>
<th>Correct Answer Weight</th>
<th>Student Answer Weight</th>
<th>Student ID</th>
</tr>
<?php
while ($row = mysql_fetch_array($result)) {
if ($row['StudentAnswer'] == $row['AnswerId']) { $row['StudentAnswerWeight'] = $row['Weight%']; } else { $row['StudentAnswerWeight'] = '0'; }
$row['StudentAnswer'] == $row['AnswerContent'];
echo "
<tr>
<td>{$row['SessionId']}</td>
<td>{$row['QuestionNo']}</td>
<td>{$row['QuestionContent']}</td>
<td>{$row['AnswerContent']}</td>
<td>{$row['StudentAnswerContent']} </td>
<td>{$row['Weight%']}</td>
<td>{$row['StudentAnswerWeight']}</td>
<td>{$row['StudentId']}</td>
</tr>";
}
?>
</table>
<?php
}
?>
謝謝:)
您是否嘗試過當你有clausole WHERE做的var_dump？ –
是的，我確實嘗試過沒有任何東西。在左邊加入之前，我做了內部連接並且它工作正常，但我被告知要這樣做， – BruceyBandit
您必須提供更多信息才能幫助您。 –