error query union

[mrprogman]

alguien sabe por que me marca este error:

All the queries in a query expression containing a UNION operator must have the same number of expressions in their select lists.

select S.SID, Sum(Contado) AS Contado, Sum(Credito) as Credito
from (

Select
[SALES2].SID, sum([SALES2].Venta)*1.11 AS Contado,
0 AS Credito
FROM [SALES2]
WHERE
[SALES2].venta<>0
And [SALES2].idate ='10/26/2011'
And [SALES2].type In (2,3)
GROUP BY [SALES2].idate, [SALES2].SID
union
Select
0 AS Contado,
sum([SALES2].Venta)*1.11 AS Credito
FROM [SALES2]
WHERE [SALES2].sid IN (1,2,4,5,8,10,12,16,18,19,20,21)
And [SALES2].venta<>0
And [SALES2].idate ='10/26/2011'
And [SALES2].type In (0,1)
GROUP BY [SALES2].idate, [SALES2].SID

) as S
group by SID

saludos....y gracias por su respuesta