我使用sql的代码php有一些问题

Question

我的问题是PHP无法正确执行我想执行的以下SQL命令：

DELETE FROM student
WHERE student.id NOT IN (SELECT studentImport.id FROM studentImport);

从mysql中，我输入sql命令并完美运行，当我使用php擦除所有数据时运行该问题。 想法是在php中运行该sql，因为我在一个新表中进行了导入，如果它们不匹配，则与第一个表进行比较，ID将从第一个表中删除。 这个想法如下：

student:
=============
id | name
1  | Oriol
2  | Ricard

studentImport
=============
id | name
1  | Oriol

结果将是：

student:
=============
id | name
1  | Oriol

studentImport:
=============
id | name
1  | Oriol

我的php代码如下：

class csv extends mysqli {

    private $state_csv = false;

    public function __construct() {

        parent::__construct("localhost","","","");

        if ($this->connect_error) {
            echo "File to connect Database: ". $this ->connect_error;
        }
    }

    public function import($file=''){
        $file = fopen($file, 'r');

        while ($row = fgetcsv($file)) {

            $value = '"'. implode('","', $row) .'"';
            $q = "INSERT INTO studentImport(id,nome) VALUES(". $value .")";
            if ($this->query($q)) {
                $this->state_csv = true;
                $deleteOldStudent = "DELETE FROM student WHERE student.id NOT IN (SELECT studentImport.id FROM studentImport);";
                if ($this->query($deleteOldStudent)) {
                    $this->state_csv = true;
                } else {
                    $this->state_csv = false;
            } else {
                $this->state_csv = false;
            }
        }
    }
}