ช่วยดูให้หน่อย ติดอยู่หลายวันแล้ว SELECT serve_id FROM serve where

<?php
  include "connectdb.php";
   $sql = "SELECT  serve_id  FROM serve  where serve_id='$serve_id' "; 
					//echo $sql;exit;
					$result = mysql_query( $sql ) or die ("เอ็กซิคิวต์คิวรีไม่ได้"); 

					$num =  mysql_num_rows ( $result ); 
					if ( $num != 0 ) 
						{ 
						
					echo "<script>alert('เลขที่ใบสั่งซื้อเคมีภัณฑ์นี้มีอยู่แล้ว'); window.history.go(-1);</script>";
					exit;	}

for($i=0;$i<=count($cloth_id);$i++){
$cloth_id1=$cloth_id[$i];
$get_count1=$get_count[$cloth_id1];
$service_charge1=$service_charge[$cloth_id1];
//echo"$p_id1   $get_count1  $get_price1 <BR>";
if(($get_count1<>'')and($get_count1<=0)){
echo "<script>alert('จำนวนต้องมากกว่าศูนย์');window.location.href ='invoice_form.php';</script>";	
exit;
}
}
$num=1;
for($n=0;$n<=count($cloth_id);$n++){
$cloth_id2=$cloth_id[$n];
$get_count2=$get_count[$cloth_id2];
$service_charge2=$service_charge[$cloth_id2];
if(($get_count2<>'')and($get_count2>0)){
$sum=$get_count2*$service_charge;
$serve_total=$serve_total+$sum;
$sql1 = "insert into serve_detail (cloth_id,serve_id,serve_count)values('$cloth_id2','$serve_id','$get_count2')"; 
//echo $sql;exit;
$result1 = mysql_query( $sql1 ) or die (mysql_error()); 
if(($get_count2<>'')and($get_count2>0)and ($num==1)){$num++;
$sql = "insert into serve (serve_id,cus_id,serve_date, serve_total)values('$serve_id','$cus_id',CURDATE(),'$serve_total')"; 
//echo $sql;exit;
$result = mysql_query( $sql ) or die ("เอ็กซิคิวต์คิวรีไม่ได้"); 
}
}
}

		echo "<script>alert('บันทึกข้อมูลเรียบร้อยแล้ว'); window.location.href ='invoice_list.php';</script>";	

			?>


?>