Sql ISNULL condition in Sql Pivot and Sql case - sql

Question

I searched for many solutions on SO and elsewhere but couldn't quite understand how to write a query for my problem.
Anyway my query looks like below
SELECT * FROM
(
SELECT Id, Date, Name, Amount,
CASE
WHEN DATEDIFF(DAY,Date,GETDATE()) <=0
THEN 'Current'
WHEN DATEDIFF(DAY,Date,GETDATE()) <30
THEN 'Due30'
WHEN DATEDIFF(DAY,Date,GETDATE()) <60
THEN 'Due60'
ELSE 'Due90'
END AS [Age]
FROM Statement
WHERE (Amount <> 0)
) AS S
PIVOT
(
SUM(Amount)
FOR[Age] IN ([Current],[Due30],[Due60],[Due90])
) P
and the result looks like this
Id Date Name Current Due30 Due60 Due90
----------- ---------- --------------------------------------------
1 2016-04-03 Alan NULL NULL NULL 110.00
2 2016-05-02 TC NULL NULL 30.00 NULL
where should i insert IsNull condition to be able to remove the null in the result and add a zero there.
I tried inserting IsNull in the pivot query but we all know that is not meant to work

Answer 1

You have to add it repetitively in the final SELECT, when you replace the SELECT * (which should only exist in ad-hoc queries or EXISTS tests) with the column list:
SELECT
Id,
Date,
Name,
COALESCE([Current],0) as [Current],
COALESCE(Due30,0) as Due30,
COALESCE(Due60,0) as Due60,
COALESCE(Due90,0) as Due90
FROM
(
SELECT Id, Date, Name, Amount,
CASE
WHEN DATEDIFF(DAY,Date,GETDATE()) <=0
THEN 'Current'
WHEN DATEDIFF(DAY,Date,GETDATE()) <30
THEN 'Due30'
WHEN DATEDIFF(DAY,Date,GETDATE()) <60
THEN 'Due60'
ELSE 'Due90'
END AS [Age]
FROM Statement
WHERE (Amount <> 0)
) AS S
PIVOT
(
SUM(Amount)
FOR[Age] IN ([Current],[Due30],[Due60],[Due90])
) P
I've also used COALESCE since it's generally the preferred option (ANSI standard, extends to more than two arguments, applies normal type precedence rules) instead of ISNULL.

Answer 2

SELECT Id
, [Date]
, Name
, [Current] = SUM(CASE WHEN val <= 0 THEN Amount ELSE 0 END)
, Due30 = SUM(CASE WHEN val < 30 THEN Amount ELSE 0 END)
, Due60 = SUM(CASE WHEN val < 60 THEN Amount ELSE 0 END)
, Due90 = SUM(CASE WHEN val >= 60 THEN Amount ELSE 0 END)
FROM dbo.[Statement] t
CROSS APPLY (
SELECT val = DATEDIFF(DAY, [Date], GETDATE())
) s
WHERE Amount <> 0
GROUP BY Id, [Date], Name