Try This
SELECT T0.[CardCode],
T0.[DocEntry],
T0.[CardName],
T0.[DocNum],
T0.[DocStatus],
T0.[DocDate],
T0.[DocDueDate],
T0.[DocTotal],
T0.PaidToDate,
T1.[DocDate] 'Payment Date',
T2.[DocNum],
T3.[U_ARExecutives],
T4.[Descr] 'AR executive',
(T0.DocTotal - T0.PaidToDate) AS 'Remaining Balance',
ISNULL(
(
SELECT T0.DocTotal - T0.PaidToDate
WHERE DATEDIFF(DAY, T0.DocDueDate, GETDATE()) >= 0
AND DATEDIFF(DAY, T0.DocDueDate, GETDATE()) <= 30
),
0
) 'Current',
ISNULL(
(
SELECT T0.DocTotal - T0.PaidToDate
WHERE DATEDIFF(DAY, T0.DocDueDate, GETDATE()) > 30
AND DATEDIFF(DAY, T0.DocDueDate, GETDATE()) <= 60
),
0
) '31-60 Days',
ISNULL(
(
SELECT T0.DocTotal - T0.PaidToDate
WHERE DATEDIFF(DAY, T0.DocDueDate, GETDATE()) > 60
AND DATEDIFF(DAY, T0.DocDueDate, GETDATE()) <= 90
),
0
) '61-90 Days',
ISNULL(
(
SELECT T0.DocTotal - T0.PaidToDate
WHERE DATEDIFF(DAY, T0.DocDueDate, GETDATE()) > 90
AND DATEDIFF(DAY, T0.DocDueDate, GETDATE()) <= 120
),
0
) '91-120 Days'
FROM dbo.OINV T0
INNER JOIN OCRD T3
ON T0.CardCode = T3.CardCode
LEFT JOIN UFD1 T4
ON T4.FldValue = T3.U_ARExecutives
LEFT JOIN ORCT T1
ON T0.ReceiptNum = T1.DocEntry
LEFT JOIN RCT1 T2
ON T1.DocNum = T2.DocNum
WHERE T0.DocDate >= '[%0]'
AND T0.DocDate <= '[%1]'
AND T4.TableId = 'OCRD