Need to group & sum items & sub items into one record

Question

I'm having an issue creating a report that can group & sum similar items together (I know in some ways, the requirement doesn't make sense, but it's what the client wants).
I have a table of items (i.e. products).  In some cases, items can be components of another item (called "Kits").  In this scenario, we consider the kit itself, the "parent item" and the components within the kit are called
"child items".  In our Items table, we have a field called "Parent_Item_Id".  Records for Child Items contain the Item Id of the parent.  So a sample of my database would be the following:
ItemId | Parent_Item_Id | Name | QuantityAvailable
1 | NULL | Kit A | 10
2 | 1 | Item 1 | 2
3 | 1 | Item 2 | 3
4 | NULL | Kit B | 4
5 | 4 | Item 3 | 21
6 | NULL | Item 4 | 100
Item's 2 & 3 are child items of "Kit A", Item 5 is a child item of "Kit
B" and Item 6 is just a stand alone item.
So, in my report, the client wants to see the SUM of both the kit & its components in a single line, grouped by the parent item.  So an example of the report would be the following:
Name | Available Qty
Kit A | 15
Kit B | 25
Item 4 | 100
Any idea how I can setup my report to group properly?
Thanks in advance.

Answer 1

Hi Goalie,
I couldn't not able to understand that what is the base input shown. whether it is the data-set or any base table.
If it is a base table then you can use the following query to grab your output.
If you don't want to group in the query then you can return the simple select of the output  and group in the tablex it self.
/******************* Data preparation *******************/
DECLARE @TableData AS TABLE (ItemId TINYINT, ParentItemId TINYINT, Name VARCHAR(10) , QuantityAvailable TINYINT)
INSERT INTO @TableData (ItemId, ParentItemId, Name, QuantityAvailable)
VALUES (1, NULL, 'Kit_A', 10)
      ,(2, 1, 'Item_1', 2)
 ,(3, 1, 'Item_2', 3)
 ,(4, NULL, 'Kit_B', 4)
 ,(5, 4, 'Item_3', 21)
 ,(6, NULL, 'Item_4', 100)
/******************* Main Query *******************/
;WITH CTE_Data
AS
SELECT RwDt.ItemId, RwDt.ParentItemId, RwDt.Name, RwDt.QuantityAvailable
FROM @TableData RwDt
WHERE ParentItemId IS NULL
UNION ALL
SELECT   Tp.ItemId
  , COALESCE(Tp.ParentItemId,CTE_Data.ParentItemId)
  , CTE_Data.Name
  , Tp.QuantityAvailable
FROM @TableData Tp
INNER JOIN CTE_Data ON TP.ParentItemId = CTE_Data.ItemId
SELECT NAME
     , SUM(QuantityAvailable) QuantityAvailable
FROM CTE_Data
GROUP BY NAME
Kindly mark it answer if it helps you..
Cheers.
Shivendra