ช่วยดูโค้ด mysqli_fetch_array ซ้อนกันหน่อยครับ error mysqli_fetch_array() expects parameter 1 to be mysqli_result ตอนใส่ where

<?php
  $sql ="SELECT *  FROM product AS t1 INNER JOIN sections  AS t2 ON  (t1.s_id = t2.s_id)INNER JOIN unit  AS t3 ON  (t1.u_id = t3.u_id)";
	$result = mysqli_query($db,$sql);
       while($row = mysqli_fetch_array($result))
 {
$sql5='SELECT *  FROM tb_pd_in AS t1 INNER JOIN saler  AS t2 ON  (t1.sale_id = t2.sale_id)INNER JOIN unit  AS t3 ON  (t1.u_id = t3.u_id)INNER JOIN product  AS t4 ON  (t1.p_id = t4.p_id) where p_id = '.$row["p_id"].' ';
$query=mysqli_query($db,$sql5);
while($rs = mysqli_fetch_array($query)){
 }
         

  }



	?>