Infoset query SELECT SUM issue - select

Question

I am trying to sum all quantities (MENGE) lines where PO number (EBELN) AND item number in the corresponding PO (EBELP) and Movement type (BWART) "101" then subtract an equivalent table with Movement type "102" to get the final quantity as the result.
Currently I added 2 custom fields, one for 101 and one for 102 movement, to break it down and see the results. With my current code, the report shows the correct data for 101 column, but returns a lot of rubbish for 102: it has the correct data, but it returns numbers/data where there should be none and I can't figure out why or where is it pulling the numbers from.
The code below:
*DATA TAB
DATA: itab1 like table of mseg,
wa1 like mseg,
wa2 like mseg.
DATA: *mseg like table of mseg.
DATA: itab3 like table of ekbe,
wa3 like ekbe.
Data: *ekbe like table of ekbe.
data: QNT101_menge like mseg-menge,
QNT102_menge like mseg-menge,
QNT103_MENGE LIKE EKBE-MENGE.`
*Record Processing TAB
if sy-subrc eq 0.
wa1-ebeln = mseg-ebeln.
wa1-menge = mseg-menge.
wa1-ebelp = mseg-ebelp.
wa1-bwart = mseg-bwart.
wa2-ebeln = mseg-ebeln.
wa2-ebelp = mseg-ebelp.
wa2-menge = mseg-menge.
wa2-bwart = mseg-bwart.
Select: sum( menge ) as menge into QNT101_menge
from mseg
where ebeln = wa1-ebeln
and ebelp = wa1-ebelp
and bwart = 101
group by ebeln ebelp.
endselect.
clear *mseg.
Select sum( menge ) as menge into QNT102_menge
from mseg
where ebeln = wa1-ebeln
and ebelp = wa1-ebelp
and bwart = 102
group by ebeln ebelp.
endselect.
append wa1 to itab1.
clear wa1.
endif.
And my custom fields only have some basic code like
ACTUALQNT2 = QNT102_MENGE.
There are more variables than I use, because I plan on building the report further.

Answer 1

The problem is in the select statements.
You're accessing MSEG with single values of EBELN and EBELP at a time, taken the values from wa1 structure and using an aggregate sum.
You don't need to group by, since you are not accessing with multiple EBELN, EBELP values.
Also the ENDSELECT statement produces a sort of "loop" in MSEG DB table that is not needed.
Try using the following:
Select sum( menge ) as menge into QNT101_menge
from mseg
where ebeln = wa1-ebeln
and ebelp = wa1-ebelp
and bwart = '101'.
Select sum( menge ) as menge into QNT102_menge
from mseg
where ebeln = wa1-ebeln
and ebelp = wa1-ebelp
and bwart = '102'.
Also for performance reasons you should try to not access DB when not needed (you were selecting twice with almost the same criteria).
Here's a better version
Gets a table of quantities summed by movement type (101 or 102)
select bwart, sum( menge ) as menge
from mseg
into table #data(lt_quantity)
where ebeln = #wa1-ebeln
and ebelp = #wa1-ebelp
and bwart in ( '101' , '102' )
group by bwart.
Then reads from internal table the values you want. (here the optional is needed to avoid an execption if the mov.type is not present)
qnt101_menge = value #( lt_quantity[ bwart = '101']-menge optional ).
qnt102_menge = value #( lt_quantity[ bwart = '102']-menge optional ).
EDIT: inline declarations
starting from ABAP 7.40 you can use inline declaration directly into the SELECT statement. (see documentation)
Table lt_quantity is declared on the fly, in the moment the select statement is performed. You don't need to declare the table before, but instead the system creates it with the proper structure dynamically.
To use those new functionalities you must use the # symbol before every variable used (so also when using #wa1)
If your system version does not support this syntax yet, here's the classic version of the statement. Please note the classic SELECT syntax also differs from the new one (no commas between fields, no #, INTO part declared at the bottom of the statement)
types: begin of qty_type,
bwart type mseg-bwart,
menge type mseg-menge,
end of qty_type.
data: lt_quantity type table of qty_type.
select bwart sum( menge ) as menge
from mseg
into table lt_quantity
where ebeln = wa1-ebeln
and ebelp = wa1-ebelp
and bwart in ( '101' , '102' )
group by bwart.