SAP Query Difficulties

Question

I have a requirement which I'm not quite sure how to get around.
I'm writing a query based on Sales Documents and Delivery Documents.
I am using table joins between VBAK, VBAP, VBFA, LIKP, LIPS, and VBUP.
The output I want is to display the shortage on deliveries compared to sales orders where applicable. I calculate this by Sales Order Quantity - Delivery Quantity.
I have nearly been able to get the output I want, however consider this scenario:
A customer orders 20 of a particular item.
10 of these are packed and delivered. Then, in the same night, the rest of the items are packed and delivered.
This means there is one item on the Sales Order with quantity 20, and two items on the delivery notes of 10 and 10.
The output I receive in this instance is as such:
  Depot       
Material
Description                         
Short or Over
Sales Order Qty
Delivery Qty
Sales Order No
Sales order Item
  FAVERSHAM   
111111
Material 1
1
33
32
443011
60
  FAVERSHAM   
111111
Material 1
32
33
1
443011
60
  CREWE       
111112
Material 2
1
10
9
443020
50
  CREWE       
111112
Material 3
4
15
11
443020
10
Material 1 hasn't had a shortage...it's just been delivered in two separate packs of 1 and 32 to add up to the order quantity of 33, so it shouldn't be displayed at all.
Materials 2 and 3 are displaying fine because there's only one delivery note assigned to them thus far.
How can I get around this issue?
Thanks in advance.

Answer 1

I am carrying this report out in SQ01.
All the joins have been achieved with the standard infoset  functionality.
Within a custom field 'SHORTS' I have the following code (I know it's not right but can't figure out how to write the correct code in to achieve desired results):
DATA:
begin of WA_FINAL,
VBELV like VBFA-VBELV,
POSNV like VBFA-POSNV,
VBELN like VBFA-VBELN,
POSNN like VBFA-POSNN,
KWMENG like VBAP-KWMENG,
LFIMG like LIPS-LFIMG,
end of WA_FINAL,
I_FINAL like standard table of WA_FINAL with header line,
l_sum  like LIPS-LFIMG,
wa_del_sent like LIPS-LFIMG.
SELECT
VBELV POSNV VBELV POSNV
INTO
I_FINAL
FROM
VBFA.
ENDSELECT.
SELECT
KWMENG
FROM
VBAP
INTO
I_FINAL for all entries in I_FINAL
WHERE
VBELN = I_FINAL-VBELV AND POSNR = I_FINAL-POSNV.
ENDSELECT.
SELECT
LFIMG
FROM
LIPS
INTO
I_FINAL for all entries in I_FINAL
WHERE
VBELN = I_FINAL-VBELN AND POSNR = I_FINAL-POSNN.
ENDSELECT.
  loop at I_FINAL into WA_FINAL.
    if sy-tabix = 1.
l_sum  =  WA_FINAL-LFIMG.
     WA_FINAL-LFIMG  =  WA_FINAL-LFIMG.
     SHORTS = WA_FINAL-KWMENG - WA_FINAL-LFIMG.
     wa_del_sent  =  WA_FINAL-LFIMG.
    else .
      l_sum  =  wa_del_sent  +  l_sum.
      SHORTS =  WA_FINAL-KWMENG  -  l_sum.
    endif.
  endloop.