Mini Shell

<?php
include '../db/database.php'; 
$year1 = $_GET['year1'];
$year=(date("Y")+543);

 $sql = "INSERT INTO subject (subject_class_id,subject_name,credit,subject_code,academic_year,course) SELECT subject_class_id,subject_name,credit,subject_code,$year,course FROM subject WHERE academic_year = '$year1'";
 $result = mysqli_query($link2, $sql);
    
 if ($result){ 
     echo  "<script>window.location='subject.php';</script>";
    } else {
       echo "<script>alert('เกิดข้อผิดผลาด ! ไม่สามารถบันทึกข้อมูลได้');window.location='subject.php';</script>";
    }