Hi Delanoe
find the query below i think this will solve your problem
SELECT T0.[DocNum], T0.[CardCode], T0.[CardName],
convert(varchar(10),T0.[DocDate],102), convert(varchar(10),T0.[DocDueDate],102),
convert(float,T0.[VatSum]), T0.[DiscSum], convert(float,T0.[DocTotal]),
convert(float,T0.[GrosProfit]), T0.[Ref1], T0.[Ref2], T0.[Comments],
T0.[JrnlMemo], T1.[SlpCode], T1.[SlpName], convert(float,T0.[Weight]),
T0.[WeightUnit], convert(float,T0.[Volume]), T0.[VolUnit]
FROM OINV T0 INNER JOIN OSLP T1 ON T0.SlpCode = T1.SlpCode
where T0.[DocDate]>= '01.01.13'
Regards
Jenny