如何在一个页面中将变量从一个php代码块传递给另一个？

Question

I am getting error to this probably, $result = mysql_query("Select setyear, YearName from tblset, tblyear where tblyear.ID=tblset.setyear group by setyear having tblset.setcours=".$res, $connection);

I want to pass the value of select name="studcourse" class="form-control"** which is in variable $res and put it on the $result variable under **select name="studyear" class="form-control".

Can anybody help me?

<form method="post" action="<?php echo $_SERVER['$PHP_SELF'];?>">
<div class="form-group">
<label>Student Course</label> 
<select name="studcourse" class="form-control">

   <?php
     $result = mysql_query("Select setcours, course_desc from tblset, tbl_coursetype where tbl_coursetype.course_no=tblset.setcours group by setcours", $connection);

     if (!$result) {
     die("Database query failed: " . mysql_error());
     }
     // 4. Use returned data
     while ($row = mysql_fetch_array($result)) {  
     echo "<option value=\"{$row[0]}\">{$row[1]}</option>";  
     }
  ?>

  <?php
  $res="";
  $res=$_POST["studcourse"];
  ?>
</select> 
</div>

<div class="form-group">
<label>Student Year</label> 
<select name="studyear" class="form-control">

  <?php
     $result = mysql_query("Select setyear, YearName from tblset, tblyear where tblyear.ID=tblset.setyear group by setyear having tblset.setcours=".$res, $connection);
     if (!$result) {
     die("Database query failed: " . mysql_error());
     }
     // 4. Use returned data
     while ($row = mysql_fetch_array($result)) {  
     echo "<option value=\"{$row[0]}\">{$row[1]}</option>";  
     }
?>
</select> 
</div>

Answer 1

You can pass one variable to another php using session variables :

<? Php 
session_start(); 
$z=3;
$_SESSION['var_name'] =$z;? >

Second php :

<? Php
session_start() ;
$x=$_SESSION['var_name'] ;? >