drt3751 2017-03-24 21:40
浏览 55
已采纳

使用PDO选择包含参数的连接表

Can somebody tell me pls where the error is in my code below? I have been trying to join two tables to get exam scores but I always get the error that `Warning: PDOStatement:execute(): SQLSTATE[HY093]: Invalid parameter number: parameter was not defined in C:direcory'

Here is my code:

function getEmptyExamScores($conn, $course_code, $level, $year, $semester) { 
$stmt = $conn->prepare('SELECT * FROM exams INNER JOIN register_course ON exams.course_code = register_course.course_code WHERE exams.course_code = :exams.course_code AND level = :level AND year = :year AND semester = :semester;');
$stmt->execute(['exams.course_code' => $course_code, 'level' => $level, 'year' => $year, 'semester' => $semester]);
return $stmt->fetchAll(); 
}
  • 写回答

1条回答 默认 最新

  • duandoucou7200 2017-03-24 22:07
    关注

    First advice: readability matters :-)

    I'd suggest using SQL alias for your tables, because it makes queries easier to read.

    Also you can specify which columns belong to which table. Otherwise, let's say a year from now you have a year column on both tables, and your query is going to fail because the parser won't know which column you are referring to.

    I'm assuming level, year and semester are part of the exams table.

    <?php
    
    function getEmptyExamScores($conn, $course_code, $level, $year, $semester) {
        $query = 'SELECT *
            FROM exams e
            INNER JOIN register_course rc ON e.course_code = rc.course_code
            WHERE e.course_code = :course_code
                AND e.level = :level
                AND e.year = :year
                AND e.semester = :semester';
    
        $stmt = $conn->prepare($query);
    
        $stmt->execute([
            'course_code' => $course_code,
            'level' => $level,
            'year' => $year,
            'semester' => $semester,
        ]);
    
        return $stmt->fetchAll();
    }
    
    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论

报告相同问题?

悬赏问题

  • ¥30 帮我写一段可以读取LD2450数据并计算距离的Arduino代码
  • ¥15 C#调用python代码(python带有库)
  • ¥15 矩阵加法的规则是两个矩阵中对应位置的数的绝对值进行加和
  • ¥15 活动选择题。最多可以参加几个项目?
  • ¥15 飞机曲面部件如机翼,壁板等具体的孔位模型
  • ¥15 vs2019中数据导出问题
  • ¥20 云服务Linux系统TCP-MSS值修改?
  • ¥20 关于#单片机#的问题:项目:使用模拟iic与ov2640通讯环境:F407问题:读取的ID号总是0xff,自己调了调发现在读从机数据时,SDA线上并未有信号变化(语言-c语言)
  • ¥20 怎么在stm32门禁成品上增加查询记录功能
  • ¥15 Source insight编写代码后使用CCS5.2版本import之后,代码跳到注释行里面