WITH product_po AS (
    SELECT product_id
    FROM pu_po A
    INNER JOIN pu_po_item B ON B.po_id = A.po_id
    INNER JOIN pu_po_internal_doc_no C ON C.ref_doc_no = A.doc_no
    INNER JOIN pu_po_internal D ON D.po_internal_id = C.po_internal_id
    WHERE A.doc_no = 'GOP/00841/201612' AND A.ou_id = 12
)
SELECT A.doc_no AS so_no, A.doc_date AS so_date,
f_get_product_code(B.product_id) AS product_code, f_get_product_name(B.product_id) AS product_code,
B.nett_item_amount AS so_item_amount, E.doc_no AS sales_invoice_no, D.ref_item_amount AS sales_invoice_item_amount, A.curr_code
FROM sl_so A
INNER JOIN sl_so_item B ON B.so_id = A.so_id
INNER JOIN sl_do_item C ON C.ref_id = B.so_item_id
INNER JOIN sl_invoice_item D ON D.ref_item_id = C.do_item_id
INNER JOIN sl_invoice E ON E.invoice_id = D.invoice_id
LEFT JOIN product_po F ON F.product_id = B.product_id
WHERE A.doc_no = 'GSON/02114/201612' AND A.ou_id = 13