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可能重复：
mysqli 代码和 call_user_func_array() 中出现的错误

尝试使用 mysqli 创建动态 where 子句时遇到很多错误：

警告：mysqli_stmt::bind_param() 的参数 2 应为参考，在第 319 行的 ... 中给出的值

警告：mysqli_stmt::execute(): (HY000/2031): 没有为第 328 行的准备好的语句中的参数提供数据

我猜想解决问题需要进行一些更改，但是如果两个下拉菜单中的一个不相等All或两者都不相等All，则会出现错误。

下面是显示下拉菜单和查询（带有动态 where 子句）的代码，具体取决于所选的 n 个选项：

PHP/MYSQLI:

  function StudentAnswers()
    {


/*BELOW IS THE QUERY WHERE I AM TRYING TO RETRIEVE DATA DEPENDING ON THE ASSESSMENT CHOSEN AND
THEN DEPENDING ON OPTIONS CHOSEN IN STUDENT AND QUESTION NUMBER DROP DOWN MENU */

    $selectedstudentanswerqry = "
    SELECT
    StudentAlias, StudentForename, StudentSurname, q.SessionId, QuestionNo, QuestionContent, o.OptionType, q.NoofAnswers, GROUP_CONCAT( DISTINCT Answer
    ORDER BY Answer SEPARATOR ',' ) AS Answer, r.ReplyType, QuestionMarks, 
    GROUP_CONCAT(DISTINCT StudentAnswer ORDER BY StudentAnswer SEPARATOR ',') AS StudentAnswer, ResponseTime, MouseClick, StudentMark
    FROM Student s
    INNER JOIN Student_Answer sa ON (s.StudentId = sa.StudentId)
    INNER JOIN Student_Response sr ON (sa.StudentId = sr.StudentId)
    INNER JOIN Question q ON (sa.QuestionId = q.QuestionId)
    INNER 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
    ";

    // Initially empty
    $where = array('q.SessionId = ?');
    $parameters = array($_POST["session"]);
    $parameterTypes = 'i';

    // Check whether a specific student was selected
    if($_POST["student"] !== 'All') {
        $where[] = 'sa.StudentId = ?';
        $parameters[] = $_POST["student"];
        $parameterTypes .= 'i';
    }

    // Check whether a specific question was selected
    // NB: This is not an else if!
    if($_POST["question"] !== 'All') {
        $where[] = 'q.QuestionId = ?';
        $parameters[] = $_POST["question"];
        $parameterTypes .= 'i';
    }

    // If we added to $where in any of the conditionals, we need a WHERE clause in
    // our query
    if(!empty($where)) {
        $selectedstudentanswerqry .= ' WHERE ' . implode(' AND ', $where);
        global $mysqli;
        $selectedstudentanswerstmt=$mysqli->prepare($selectedstudentanswerqry);
        // You only need to call bind_param once
            call_user_func_array(array($selectedstudentanswerstmt, 'bind_param'),
            array_merge(array($parameterTypes), $parameters)); //LINE 319 ERROR 1
    }

//Add group by and order by clause to query
    $selectedstudentanswerqry .= "
      GROUP BY sa.StudentId, q.QuestionId
      ORDER BY StudentAlias, q.SessionId, QuestionNo
    ";

    // get result and assign variables (prefix with db)
    $selectedstudentanswerstmt->execute(); //LINE 328 ERROR 2

//bind database fields $selectedstudentanswerstmt->bind_result($detailsStudentAlias,$detailsStudentForename,$detailsStudentSurname,$detailsSessionId,$detailsQuestionNo, 
    $detailsQuestonContent,$detailsOptionType,$detailsNoofAnswers,$detailsAnswer,$detailsReplyType,$detailsQuestionMarks,$detailsStudentAnswer,$detailsResponseTime,
    $detailsMouseClick,$detailsStudentMark); //LINE 331 ERROR 3

//store results retrieved
    $selectedstudentanswerstmt->store_result(); //LINE 332 ERROR 4

//count number of rows retrieved
    $selectedstudentanswernum = $selectedstudentanswerstmt->num_rows();     

//output query
    echo "$selectedstudentanswerqry";

    }

    ?>
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