SELECT m.*,b.amountB
FROM
(
SELECT d.Nbr,
d.amount,
COALESCE(d.idA,c.idA) AS idA,
COALESCE(d.idB,c.idB) AS idB,
COALESCE(d.idC,c.idC) AS idC,
c.amountC 
FROM tableD d
FULL OUTER JOIN tableC c
ON c.idA = d.idA
AND c.idB = d.idB 
AND c.idC = d.idC 
)m
LEFT JOIN [tableB] b
ON b.idA = m.idA
AND b.idB = m.idB 

Select x.Nbr, MAX(x.amount) As Amount, MAX(x.idA) As idA, MAX(x.idB) As idB, MAX(x.idC) As idC, MIN(x.amountB) As amountB, MIN(x.amountC) As amountC From
	(Select D.Nbr, D.amount, Coalesce(D.idA, c.IdA) As idA, Coalesce(D.idB, c.IdB) As idB, Coalesce(D.idC, c.IdC) As idC, B.amountB, C.amountC From A
	 JOIN B ON A.IdA = B.idA
	 JOIN C ON A.IdA = C.idA
	 Full JOIN D ON A.IdA = D.idA) As x
Group By x.Nbr