ช่วยหน่อยครับมันขึ้น...Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in

<?
$id_edit=$_GET[id_edit];

include"connect.php";
//$sql="select * from job where job_id='$id_edit'";
$sql="select job.job_id,job.job_fname,job.job_lname,job.job_detail,job.job_tel,job.job_status,job.job_remark,job.job_tel,
job.job_date,job.job_ans,job.job_ansn,job.job_update,dep.dep_name,type.type_name,company.company_name
from job,dep,type,company
where job.ref_company_id=company.company_id and job.ref_dep_id=dep.dep_id and job.ref_type_id=type.type_id and job.job_id='$id_edit'";
$result=mysql_db_query($dbname,$sql);
$rs=mysql_fetch_array($result);
$job_date=$rs[job_date];
$y=substr($job_date,2,2);
$m=substr($job_date,5,2);
$d=substr($job_date,8,2);
$job_id = $rs[job_id];
$code=sprintf("$y$m%05d",$job_id);
$job_fname=$rs[job_fname];
$job_lname=$rs[job_lname];
$company_name=$rs[company_name];
$job_detail=$rs[job_detail];
$dep_name=$rs[dep_name];
$job_update=$rs[job_update];
$job_ans=$rs[job_ans];
$job_ansn=$rs[job_ansn];
$type_name=$rs[type_name];
$job_remark=$rs[job_remark];
$job_tel=$rs[job_tel];
$job_status=$rs[job_status];

?>