helper functions

function getSumProductPurchaseAmount($product_id){
$CI=&get_instance();
$result=$CI->db->select_sum('amount','total')->get_where('purchase',['product_id'=>$product_id])->row()->total;
return $result;
}

function getSumProductSaleAmount($product_id){
$CI=&get_instance();
$numrows=$CI->db->get_where('sale',['product_id'=>$product_id])->num_rows();
if($numrows>0){
$result=$CI->db->select_sum('amount','total')->get_where('sale',['product_id'=>$product_id])->row()->total;
return $result;
}else{
	return 0;
}
}

function getSumProductDamageReturnAmount($product_id){
$CI=&get_instance();
$numrows=$CI->db->get_where('damage_return',['product_id'=>$product_id])->num_rows();
if($numrows>0){
$result=$CI->db->query("select *, SUM(dr.quantity*p.amount/p.quantity) as total_damaged  from purchase p JOIN purchase_details pd JOIN damage_return dr WHERE p.purchase_id=pd.id AND pd.refference_no=dr.refference_no AND p.product_id='$product_id' AND p.product_id=dr.product_id group by dr.product_id")->row()->total_damaged;
return $result;
	}else{
		return 0;
	}
}
function getSumProductPurchaseReturnAmount($product_id){
$CI=&get_instance();
$numrows=$CI->db->get_where('purchase_return',['product_id'=>$product_id])->num_rows();
if($numrows>0){
$result=$CI->db->query("select *, SUM(pr.quantity*(p.amount/p.quantity)) as total_returned from purchase p JOIN 
purchase_details pd 
JOIN purchase_return pr 
WHERE p.purchase_id=pd.id 
AND pd.refference_no=pr.refference_no
AND p.product_id='$product_id'
AND p.product_id=pr.product_id
group by pr.product_id")->row()->total_returned;
return $result;
}else{
	return 0;
}
}

function getSumProductSaleReturnAmount($product_id){
$CI=&get_instance();
$numrows=$CI->db->get_where('sale_return',['product_id'=>$product_id])->num_rows();
if($numrows>0){
$result=$CI->db->query("select *, SUM(sr.quantity*(s.amount/s.quantity)) as total_returned from sale s JOIN 
sale_details sd 
JOIN sale_return sr 
WHERE s.sale_id=sd.id 
AND sd.refference_no=sr.refference_no
AND s.product_id='$product_id'
AND s.product_id=sr.product_id
group by sr.product_id")->row()->total_returned;
return $result;
}else{
	return 0;
}
}