SQL Server CTE Hierarchy query aggregation - sql

Question

I want to calculate SUM of all children with CTE here is DDL/DML. 0 values are which I don't know and to be calculated through aggregation
CREATE TABLE [dbo].[Product]
(
[ID] [INT] IDENTITY(1,1) NOT NULL,
[Hierarchy] [VARCHAR](100) NOT NULL,
[ParentID] [INT] NULL,
[SalesAmount] [INT] NULL
) ON [PRIMARY]
GO
SET IDENTITY_INSERT [dbo].[Product] ON
GO
INSERT [dbo].[Product] ([ID], [Hierarchy], [ParentID], [SalesAmount])
VALUES (1, N'root', NULL, 0),
(2, N'T1', 1, 0),
(3, N'T2', 1, 0),
(4, N'C1', 2, 0),
(5, N'C2', 3, 0),
(6, N'C3', 2, 0),
(7, N'P1', 4, 1000),
(8, N'P2', 5, 2000),
(9, N'P3', 6, 3000)
I tried below query and it gives me following output,
WITH CT AS
(
SELECT
ID, Hierarchy, ParentID, 0 AS Level,
CAST ([Hierarchy] AS VARCHAR (MAX)) AS [Linkeage]
FROM
dbo.Product
WHERE
ParentID IS NULL
UNION ALL
SELECT
pc.ID, pc.Hierarchy, pc.ParentID, p1.Level + 1,
p1.Linkeage + ' -> ' + CAST ([pc].[Hierarchy] AS VARCHAR (MAX))
FROM
dbo.Product AS pc
JOIN
CT AS p1 ON p1.ID = pc.ParentID
),
Aggr AS
(
SELECT
TC.ParentID,
SUM(T.SalesAmount) AS sum_TotalAmt
FROM
CT TC
INNER JOIN
Product AS T ON TC.ID = T.ID
GROUP BY
TC.ParentID
)
SELECT
ID, Hierarchy, T.ParentID, Level, Linkeage, A.sum_TotalAmt
FROM
CT AS T
LEFT JOIN
Aggr AS A ON ISNULL(T.Id, T.ParentID) = A.ParentID
I need existing output + underlined rows as well.

Answer 1

I figured out by my-self by in different approach, i wanted to get aggregates of multiple group by values,
CREATE TABLE [dbo].[Product](
[ProductID] [int] IDENTITY(1,1) NOT NULL,
[ProductType] [varchar](100) NOT NULL,
[ProductCategory] [varchar](100) NOT NULL,
[ProductName] [varchar](100) NOT NULL,
[SalesAmount] [decimal]
) ON [PRIMARY]
So i can simply get output with below
select [ProductType], [ProductCategory], SUM( [SalesAmount] ) as TotalSales
from Product
GROUP BY ROLLUP (ProductType,ProductCategory)