无法每天生成自动邮件

I am unable to generate auto mail on daily bases. The issue is it is not able to generate it automatically. Where as i have a same sort of code which does generates it everyday. With all the same details. The code is exactly same except the database query.

Here is my code:

    <?php
session_start();
require("../connect.php");

/* require files for MAIL */
require("class.phpmailer.php");
require("class.smtp.php");
/* require files for MAIL ENDS */



/******** Get the list of audits done in week risk category falls under High Risk and during the previous visit also the location was under High risk category ----mail on every Saturday**********/

    $current_date = date('Y-m-d');
    //$current_date ='2015-08-22';;
    /*$start_time = time() - (6*86400);
    $start_dt = date('Y-m-d',$start_time);*/

      $pagent_array = array();
     $query="Select * from `location_details` ld
    Left Join `answer_general_qc` ans_general on ans_general.lid=ld.id
    Left Join `audit_general` general on general.qtno = ans_general.qt
    Left Join `audit_general_option` general_opt on general_opt.opt_id = ans_general.ans_remark
    where ld.completed ='1' and ld.priority != 'qc' and general.qtno ='1' and ans_general.opt = 'no'  and
    STR_TO_DATE(ld.`date_audited`,'%d-%m-%Y') = '".$current_date."'";   
    $result=mysql_query($query);

    $th_style="border-width: 1px;
    padding: 8px;
    border-style: solid;
    border-color: #666666;
    background-color: #dedede";
    $td_style="border-width: 1px;
    padding: 8px;
    border-style: solid;
    border-color: #666666;
    background-color: #ffffff";
    $table_result .="<table  align='center' rules='all' style='font-family: verdana,arial,sans-serif;font-size:11px;color:#333333;border-width: 1px;border-color: #666666;border-collapse: collapse;' border='1';>
            <thead>
            <tr>
            <th style='".$th_style."'>Sr No</th>
            <th style='".$th_style."'>Location Code</th>
            <th style='".$th_style."'>Location Name</th>
            <th style='".$th_style."'>PAgent</th>
            <th style='".$th_style."'>Address 1</th>
            <th style='".$th_style."'>Address 2</th>
            <th style='".$th_style."'>District</th>
            <th style='".$th_style."'>State</th>
            <th style='".$th_style."'>Priority</th>
            <th style='".$th_style."'>Remark by TO</th>
            <th style='".$th_style."'>Remark by TO</th>
            </tr>
            </thead>
            <tbody>";
            $sr_no=1;
    if(mysql_num_rows($result) != 0)
    {           
    while($row=mysql_fetch_array($result))
    { 

            if($row['option_text'] == "")
            {
              $option_text="Other";
            }
            else
            {
              $option_text=$row['option_text'];
            }
            $table_result .= "
            <tr>
            <td style='".$td_style."'>".$sr_no."</td>
            <td style='".$td_style."'>".$row['location']."</td>
            <td style='".$td_style."'>".$row['agent']."</td>
            <td style='".$td_style."'>".$row['pagent']."</td>
            <td style='".$td_style."'>".$row['address1']."</td>
            <td style='".$td_style."'>".$row['address2']."</td>
            <td style='".$td_style."'>".$row['district']."</td>
            <td style='".$td_style."'>".$row['state']."</td>
            <td style='".$td_style."'>".$row['priority']."</td>
            <td style='".$td_style."'>".$option_text."</td>
            <td style='".$td_style."'>".$row['qc_remark']."</td>
            </tr>";
            $sr_no++;
    }
    }
    else
    {
     $table_result .="<tr><td colspan='9' align='center'>No Locations Found</td></tr>";
    }
     $table_result .="</tbody>
                     </table>";

    //  echo $table_result;     exit;

        /* Code to send MAIL */
        $mail = new PHPMailer();
        $mail->IsSMTP();
        $mail->Host = "host";

        $mail->SMTPAuth = true;
        //$mail->SMTPSecure = "ssl";
        $mail->Port = 25;
        $mail->Username = "Username";
        $mail->Password = "Password";

        $mail->From = "From";
        $mail->FromName = "Name";

        $mail->AddAddress("Email");

        $mail->AddBCC("Email CC");



        $body = "Dear All,<br /><br />For the review conducted on ".date('d-m-Y',strtotime($current_date))." in the following locations we have found deviation in question 1.1 (ie Does this location exist exactly at the address provided?) <br /><br /><br /><br />";
        $body .= $table_result;
        $body .= "<br /><br />Warm Regards <br /><br />

Note : Please do not reply to this email as this is an automated mail generated 
";

        //end body


        $mail->IsHTML(true);
        //$mail->Subject = "Ref : RC1/HR/".strtoupper($pa)."/".date('F Y',(time()-(5*86400)));
        $mail->Subject = "Ref : Lrr 1.1 deviation";
        $mail->Body = $body;
        //$mail->AltBody = "This is the body in plain text for non-HTML mail clients";

        if(!$mail->Send())
        {
            echo "Message could not be sent. <p>";
            echo "Mailer Error: " . $mail->ErrorInfo;
            exit;
        }

        /* Code to send MAIL Ends */



        //mail($to,$subject,$message,$headers);
        echo 'Mail sent to '.$pa.'<br /><br />';


    /****** END of sending mail **********/


?>

If you want to send mails on a regular or daily basis the ideal way to do that would be to use cron job for sending the mails.By using cron you can specify what application do you want the cron to run on.Also you will be able to specify what time exactly do you want the mail to be sent. Refer here https://askubuntu.com/questions/2368/how-do-i-set-up-a-cron-job . Hope it helps.