Question

我是一个新的MySQL和PHP编码器...大约7年前曾经使用它，但现在它再次落在了我的膝盖上。目前，该代码可以吸引学生进行出勤跟踪，其工作原理如下：

$count = sqlValue("SELECT count(*) FROM `attendance` LEFT JOIN `enrollments` ON attendance.`student_class` = enrollments.id Where enrollments.class='".$class."' AND attendance.date='".$date."'");
    if ($count == 0)
    {       
        $query = "SELECT CONCAT_WS('', `students`.`fname`, ' ', `students`.`lname`)  as `student`, `classes`.`class_name` as class, enrollments.id as eid FROM `students` LEFT JOIN `enrollments` ON students.id = enrollments.student LEFT JOIN `classes` ON classes.id = enrollments.class";
        $query.= " WHERE enrollments.class='".$class."'";
        $query.= " ORDER BY students.id";

        $res   = sql($query, $eo);
        $tbody = '';$ids=array();
        if(db_num_rows($res) > 0)

这很有效，但现在他们只想展示那些活跃的＆＃34;。我在数据库中添加了一列，并对前端进行了编码，将学生标记为活动状态。所有这一切都有效，现在我想运行一个只显示活跃学生的查询，然后让我使用复选框将它们标记为该类的存在。我尝试了以下方法，但它不起作用：

$count = sqlValue("SELECT count(*) FROM `attendance` LEFT JOIN `enrollments` ON attendance.`student_class` = enrollments.id Where enrollments.class='".$class."' AND attendance.date='".$date."'");
    if ($count == 0)
    {       
        $query = "SELECT CONCAT_WS('', `students`.`fname`, ' ', `students`.`lname`)  as `student`, `classes`.`class_name` as class, enrollments.id as eid FROM `students` LEFT JOIN `enrollments` ON students.id = enrollments.student LEFT JOIN `classes` ON classes.id = enrollments.class";
        $query.= " WHERE enrollments.class='".$class."'" and enrollments.status <> 'Active';
        $query.= " ORDER BY students.id";

        $res   = sql($query, $eo);
        $tbody = '';$ids=array();
        if(db_num_rows($res) > 0)

它在第45行引发错误，即$query.= " WHERE enrollments.class='".$class."'" and enrollments.status <> 'Active';行。

结构是

    Table structure for table `enrollments`
--

CREATE TABLE IF NOT EXISTS `enrollments` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `student` int(10) unsigned DEFAULT NULL,
  `class` int(10) unsigned DEFAULT NULL,
  `enrollment_date` date NOT NULL,
  `status` varchar(40) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `student` (`student`),
  KEY `class` (`class`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 AUTO_INCREMENT=109 ;

/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;

Answer 1

"'"中还有一个引号。

该行应为：

     $query.= " WHERE enrollments.class='".$class."' and enrollments.status <> 'Active'";

只想要查询中显示的活动结果。 PHP MySQL

1 个答案: