Query to find the AP invoices that are applied to multiple Purchase Orders

1SELECT COUNT (DISTINCT d.segment1), a.invoice_num
2    FROM ap.ap_invoices_all            A,
3         ap.ap_invoice_distributions_all b,
4         po.po_distributions_all       C,
5         po.po_headers_all             d,
6         po.po_lines_all               G
7   WHERE     a.invoice_id = b.invoice_id
8         AND b.po_distribution_id = c.po_distribution_id(+)
9         AND c.po_header_id = d.po_header_id(+)
10         AND d.po_header_id = g.po_header_id
11         AND c.po_line_id = g.po_line_id
12         AND c.po_header_id IS NOT NULL
13         AND a.payment_status_flag = 'Y'
14         AND d.type_lookup_code != 'BLANKET'
15         AND a.org_id = 1234
16         AND a.org_id = d.org_id
17GROUP BY a.invoice_num
18  HAVING COUNT (DISTINCT d.segment1) > 1