Why this SUM() field not working as expected?

Question

Can you please explain me why this query is not doing the SUM(LI.Unidades) as expected? I want all rows with the same LINECOUNT to be added together.

First I also had LI.Unidades in the select and the group by (also need the LI.Unidades field without the SUM()) but I removed it just to test, and still not adding correctly.

SELECT
CASE AL.CodigoEmpresa WHEN 1 THEN '802' WHEN 100 THEN '801' ELSE 'N/A' END AS 'COMPANYID',
D365.Account as 'CUSTACCOUNT',
SUM(LI.Unidades) as 'GROSSWEIGHT',
AL.NumeroLineas as 'LINECOUNT', 
'KG' as 'SALESUNIT',
LI.ImporteBruto as 'GROSSAMOUNT'

FROM CabeceraAlbaranCliente AL inner join LineasAlbaranCliente LI on (AL.NumeroAlbaran = LI.NumeroAlbaran and AL.FechaAlbaran = Li.FechaAlbaran and AL.CodigoEmpresa = LI.CodigoEmpresa)
inner join AALPLA_D365Customers D365 on (AL.CifEuropeo = D365.Tax_exempt_number and D365.Plant = AL.CodigoEmpresa)

WHERE AL.EjercicioAlbaran = '2020' and AL.NumeroAlbaran = '14424' 

GROUP BY D365.Account, AL.CodigoEmpresa, AL.NumeroAlbaran, AL.NumeroLineas, LI.ImporteBruto

This is the result I am getting:

COMPANYID   CUSTACCOUNT GROSSWEIGHT LINECOUNT   SALESUNIT   GROSSAMOUNT
802         40801       0.0000000000    4       KG           555
802         40801       1.0000000000    4       KG           3000
802         40801       4.0000000000    4       KG           1280
802         40801       16.000000000    4       KG           112
802         40801       100.00000000    13      KG           3123
802         40801       225.00000000    13      KG           11
802         40801       500.00000000    13      KG           100
802         40801       550.00000000    13      KG           30
802         40801       750.00000000    13      KG           12
802         40801       1000.0000000    13      KG           1247
802         40801       1080.0000000    13      KG           1
802         40801       1125.0000000    13      KG           8
802         40801       1200.0000000    13      KG           1765
802         40801       1375.0000000    13      KG           987
802         40801       1475.0000000    13      KG           40
802         40801       2425.0000000    13      KG           30
802        40801        7075.0000000    13      KG           984

And what I want is:

COMPANYID   CUSTACCOUNT GROSSWEIGHT LINECOUNT   SALESUNIT   GROSSAMOUNT
802         40801       21.000000000    4       KG           555
802         40801       21.000000000    4       KG           3000
802         40801       21.000000000    4       KG           1280
802         40801       21.000000000    4       KG           112
802         40801       18880.000000    13      KG           3123
802         40801       18880.000000    13      KG           11
802         40801       18880.000000    13      KG           100
802         40801       18880.000000    13      KG           30
802         40801       18880.000000    13      KG           12
802         40801       18880.000000    13      KG           1247
802         40801       18880.000000    13      KG           1
802         40801       18880.000000    13      KG           8
802         40801       18880.000000    13      KG           1765
802         40801       18880.000000    13      KG           987
802         40801       18880.000000    13      KG           40
802         40801       18880.000000    13      KG           30
802         40801       18880.000000    13      KG           984

Answer 1

I think you want a cumulative sum, not aggregation:

SELECT (CASE AL.CodigoEmpresa WHEN 1 THEN '802' WHEN 100 THEN '801' ELSE 'N/A' END) AS COMPANYID,
       D365.Account as 'CUSTACCOUNT',
       SUM(LI.Unidades) OVER (ORDER BY LI.Unidades) as GROSSWEIGHT,
       AL.NumeroLineas as LINECOUNT, 
       'KG' as SALESUNIT,
       LI.ImporteBruto as GROSSAMOUNT
FROM CabeceraAlbaranCliente AL inner join
     LineasAlbaranCliente LI 
     ON AL.NumeroAlbaran = LI.NumeroAlbaran and
        AL.FechaAlbaran = Li.FechaAlbaran and
        AL.CodigoEmpresa = LI.CodigoEmpresa inner join
        AALPLA_D365Customers D365
        on AL.CifEuropeo = D365.Tax_exempt_number and
          D365.Plant = AL.CodigoEmpresa
WHERE AL.EjercicioAlbaran = '2020' and AL.NumeroAlbaran = '14424'