problem in validations for following code while importing csv file

 function connect_db()

            {

                    $con = mysql_connect("localhost","root","");
 
                                 if (!$con)
 
                                    {
            
                                            die('Could not connect: ' . mysql_error());
 
                                    }
                     mysql_select_db("import", $con);
            }
  
 
    if (isset($_POST['load']))
        { 
            if ( isset($_FILES["file"]))
                 {
                    //if there was an error uploading the file
                    if ($_FILES["file"]["error"] > 0) 
                            {
                                echo "File Not Selected  <br />";
                            }
                                   
                                     else 
                                    {
                                         //Print file details
                                            
                                            // echo "Upload: " . $_FILES["file"]["name"] . "<br />";
                                             
                                            // echo "Type: " . $_FILES["file"]["type"] . "<br />";
                                             
                                            // echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
                                            
                                            // echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";

                                         //if file already exists
                                                 $file_name = $_FILES["file"]["name"];
                                             if (file_exists("$file_name"))
             
                                                     {
               
                                                          echo $_FILES["file"]["name"] . " already exists. ";
          
                                                       }
             
                                           elseif($_FILES["file"]["type"] != "application/vnd.ms-excel")
                                                        { 
           	
                                                                die("This is not a CSV file.");
            
                                                        }
                                                            else 
         
                                                                    {
                                                                        //Store file in directory "upload" with the name of "uploaded_file.txt"
                                                     
                                                                    
                                                                     $location="C:\\xampp\\mysql\\data\\import\\";
          
                                                        move_uploaded_file($_FILES["file"]["tmp_name"], $location . $_FILES["file"]["name"]);
       
                
                connect_db();        
                 
         $q="LOAD DATA INFILE '$file_name' INTO TABLE import
                FIELDS TERMINATED BY '|'
                LINES TERMINATED BY '\n'
                IGNORE 1 LINES 
                (srno,@date,@mobno,@state,@type,@telecaller)
                SET srno=srno,date=@date,mobno=@mobno,
                state=@state,type=@type,telecaller=@telecaller";
                       
                                                                 
                                                                   
mysql_query($q) or die(mysql_error());
                              
     echo"File Uploaded and Updated Successfully";
                             

mysql_query("INSERT INTO temp1 SELECT mobno,telecaller FROM import GROUP BY mobno HAVING COUNT(*)>1 ") or die(mysql_error());

mysql_query("UPDATE import,temp1 SET import.telecaller=temp1.telecaller WHERE import.mobno=temp1.mobno");
                  } 
                    }
             }          
            }

?>