вы можете использовать
SELECT
ISNULL(sp.Telephone,'No Sales Employee') ,
od.CardCode,
od.CardName,
Sum(case when c.U_ItemStatus = '2' then od.DocTotal else 0 end) as Sold2018,
Sum(case when c.U_ItemStatus = '1' then od.DocTotal else 0 end) as Sold2019,
CASE WHEN Sum(case when c.U_ItemStatus = '2' then od.DocTotal else 0 end) = 0 THEN
Sum(case when c.U_ItemStatus = '1' then od.DocTotal else 0 end) END as new
FROM
ORDR od
Left Join OSLP sp
On od.SlpCode=sp.SlpCode
left join RDR1 a on a.DocEntry = od.DocEntry
left join OITM b on b.ItemCode = a.ItemCode
left Join OITB c on c.ItmsGrpCod = b.ItmsGrpCod
Group By
sp.Telephone,
od.CardCode,
od.CardName,
c.U_ItemStatus
или
SELECT *, CASE WHEN Sold2018 = 0 THEN Sold2019 END as new
FROM (
SELECT
ISNULL(sp.Telephone,'No Sales Employee') as Telephone,
od.CardCode,
od.CardName,
Sum(case when c.U_ItemStatus = '2' then od.DocTotal else 0 end) as Sold2018,
Sum(case when c.U_ItemStatus = '1' then od.DocTotal else 0 end) as Sold2019
FROM
ORDR od
Left Join OSLP sp
On od.SlpCode=sp.SlpCode
left join RDR1 a on a.DocEntry = od.DocEntry
left join OITM b on b.ItemCode = a.ItemCode
left Join OITB c on c.ItmsGrpCod = b.ItmsGrpCod
Group By
sp.Telephone,
od.CardCode,
od.CardName,
c.U_ItemStatus
) AS T