在ap_invoice_distributions_all中有时rcv_transaciton_id为空，有时却又是有值的， 这是为什么呢？（请参考po_line_locations_all.match_option）
或许你还记得我们在发票工作台上选择匹配时，有时是Match PO,有时却是Match Receipt,其实这就是原因所在， 当然影响这个匹配项的根本还是PO的shipment上的一个开关：是Receipt,还是Purchase Order,如果这里是Receipt,在匹配PO时，只能选择Receipt（匹配成功保存后rcv_transaciton_id是有值的），反之在匹配值只能选择Purchase Order（匹配成功保存后rcv_transaciton_id是没有值的）
其实在这个ap_invoice_distributions_all还有个po_distribution_id字段，不管rcv_transaciton_id是否为空，只要是和PO建立关系的，po_distribution_id字段总归是有值的。
现有这样的需求：查询----发票号码，接收号码，采购订单号码
（我总是会使用po_distribution_id作为条件，而不要使用rcv_transaciton_id）
----------------------------------------
SELECT ai.invoice_num,
rsh.receipt_num,
ph.segment1,
aid.distribution_line_number,
aid.rcv_transaction_id,
aid.po_distribution_id
FROM ap_invoices_all ai,
ap_invoice_distributions_all aid,
po_distributions_all pd,
rcv_transactions rt,
rcv_shipment_lines rsl,
rcv_shipment_headers rsh,
po_headers_all ph
WHERE ai.invoice_id = aid.invoice_id
AND aid.set_of_books_id = '&sob'
AND aid.period_name = '&period_name'
AND aid.po_distribution_id = pd.po_distribution_id
AND pd.po_distribution_id = rt.po_distribution_id
AND rt.po_distribution_id = rsl.po_distribution_id
AND rsl.shipment_line_id = rt.shipment_line_id
AND rsh.shipment_header_id = rsl.shipment_header_id
AND rt.destination_type_code = 'RECEIVING'
AND rt.po_header_id = ph.po_header_id
ORDER BY 1,
2
ap_invoice_distributions_all
line_type_Lookup_code字段，就是识别核销内容的类型。
line_type_Lookup_code值：
FREIGHT:运费
ITEM:行
PREPAY:预付款
TAX:税
