how to use aggregate functions when combining two datatables

Question

Hi,
I have two datatables in the dataset and I want to use the fields from both datatables to create a Crystal Report. But I use max and group by in the select query which when I run in access works fine. But, I don't know how to combine the datatables using aggregate functions.
I have two datatables:NalogNov and MagNov and the result query I made is:

SELECT NalogNov.DATA, Max(IIf([MagNov].[DATA]=[NalogNov].[DATA],[MagNov].[Gorivo],0)) AS Gorivo1, Max(IIf([MagNov].[DATA]=[NalogNov].[DATA],[MagNov].[Addblue],0)) AS Addblue1, Max(IIf([MagNov].[DATA]=[NalogNov].[DATA],[MagNov].[Antifriz],0)) AS Antifriz1, Max(IIf([MagNov].[DATA]=[NalogNov].[DATA],[MagNov].[Motmaslo],0)) AS Motmaslo1, NalogNov.pockm, NalogNov.krajkm, [krajkm]-[pockm] AS RAZLIKA, Max(NalogNov.Poslprov) AS MaxOfPoslprov, Max(NalogNov.Poslserv) AS MaxOfPoslserv, Max(NalogNov.KMS) AS MaxOfKMS, Max(NalogNov.KMP) AS MaxOfKMP
FROM NalogNov LEFT JOIN MagNov ON NalogNov.GBRV = MagNov.GBR
WHERE (((MagNov.GBR)=[NalogNov].[GBRV]))
GROUP BY NalogNov.DATA, NalogNov.pockm, NalogNov.krajkm, [krajkm]-[pockm]
ORDER BY NalogNov.DATA;

But how to use this query in C# creating the CrystalReport? I tried to use the CR wizard, but I have lot of rows for one data, and the values in the result CR are not correct. Can anybody help me please?Thanks