Where to apply filters

I have the following query

SELECT Item.No_, Item.Description, Table1.Inventory, Table2.[Qty on Sales Order], Table3.[Qty on Blanket Order]
FROM [CompanyName$Item] AS Item LEFT OUTER JOIN
(SELECT [Item No_], ISNULL(SUM(Quantity), 0) AS Inventory
FROM [CompanyName$Item Ledger Entry] AS ILE
GROUP BY [Item No_]) AS Table1 ON Item.No_ = Table1.[Item No_] LEFT OUTER JOIN
(SELECT No_, [Document Type], Type, ISNULL(SUM([Outstanding Quantity]), 0) AS [Qty on Sales Order]
FROM [CompanyName$Sales Line] AS SL
GROUP BY No_, [Document Type], Type) AS Table2 ON Item.No_ = Table2.No_ AND Table2.[Document Type] = 1 AND
Table2.Type = 2 LEFT OUTER JOIN
(SELECT No_, [Document Type], Type, ISNULL(SUM([Outstanding Quantity]), 0) AS [Qty on Blanket Order]
FROM [CompanyName$Sales Line] AS BSL
GROUP BY No_, [Document Type], Type) AS Table3 ON Item.No_ = Table3.No_ AND Table3.[Document Type] = 4 AND Table3.Type = 2

To get only those records from Item Table Where [Qty on Blanket Order] <> 0 OR [Qty on Sales Order] Where should i put this filter.

I assume you mean, "where Qty_on_blanket_order <> 0 or Qty_on_sales_order <> 0", right?
Since you must allow for either aggregate value to equal 0, you cannot filter within the derived tables.
At the end of the main query, simply add that WHERE clause.

Thnak you.
Thats doubt i have but its clear now. Its working perfectly now.