//$sql_requisition_items="select a.*,b.* from requisition_items a inner join tbl_items b on a.item_id=b.item_id where req_id='".$_POST['req_id']."' " ;
$sql_requisition_items=" SELECT r.*,ri.*,b.*,ifnull(st.total_qty,0) as issue_qty,ri.req_item_id,ri.req_id, trim(concat(ifnull(f.form_name,''),' ',b.item_name)) itemwithformname FROM requisition r inner join requisition_items ri on r.req_id=ri.req_id inner join tbl_items b on ri.item_id=b.item_id left join medicine_form f on b.item_form_id=f.form_id left join (SELECT req_item_id,req_id ,item_id,ifnull(sum(issue_qty),0) as total_qty FROM `stock_issue_items` group by item_id,req_item_id,req_id ) st on (st.req_id=ri.req_id and ri.item_id=st.item_id and st.req_item_id=ri.req_item_id) where (ri.qty-ifnull(st.total_qty,0))>0 and ri.req_id='".$_POST['req_id']."' ";