Multiply with 1 if 0

In the below table, quantity can be 0 for the primary record.

In case of value 0 , multiply child value with primary assigning 1 for primary value only for calculation

CREATE TABLE [dbo].[Travel_Occurs]( 
[Mode_Sno] [int] NULL,
[Mode_Id] [nchar](2) NULL,
[Mode_Parent_Sno] [int] NULL,
[Quantity] [numeric](18, 0) NULL
) ON [PRIMARY]

INSERT INTO [dbo].[Travel_Occurs] ([Mode_Sno] ,[Mode_Id], [Mode_Parent_Sno] ,[Quantity]) VALUES (1,'AP',-1,2)
INSERT INTO [dbo].[Travel_Occurs] ([Mode_Sno] ,[Mode_Id], [Mode_Parent_Sno] ,[Quantity]) VALUES (2,'SE',-1,0)
INSERT INTO [dbo].[Travel_Occurs] ([Mode_Sno] ,[Mode_Id], [Mode_Parent_Sno] ,[Quantity]) VALUES (3,'SP',1,3)
INSERT INTO [dbo].[Travel_Occurs] ([Mode_Sno] ,[Mode_Id], [Mode_Parent_Sno] ,[Quantity]) VALUES (4,'BT',1,5)
INSERT INTO [dbo].[Travel_Occurs] ([Mode_Sno] ,[Mode_Id], [Mode_Parent_Sno] ,[Quantity]) VALUES (5,'RD',-1,5)
INSERT INTO [dbo].[Travel_Occurs] ([Mode_Sno] ,[Mode_Id], [Mode_Parent_Sno] ,[Quantity]) VALUES (6,'BU',5,10)
INSERT INTO [dbo].[Travel_Occurs] ([Mode_Sno] ,[Mode_Id], [Mode_Parent_Sno] ,[Quantity]) VALUES (7,'CA',5,0)
INSERT INTO [dbo].[Travel_Occurs] ([Mode_Sno] ,[Mode_Id], [Mode_Parent_Sno] ,[Quantity]) VALUES (8,'BI',5,15)
INSERT INTO [dbo].[Travel_Occurs] ([Mode_Sno] ,[Mode_Id], [Mode_Parent_Sno] ,[Quantity]) VALUES (9,'CY',5,2)
INSERT INTO [dbo].[Travel_Occurs] ([Mode_Sno] ,[Mode_Id], [Mode_Parent_Sno] ,[Quantity]) VALUES (10,'TR',5,5)
INSERT INTO [dbo].[Travel_Occurs] ([Mode_Sno] ,[Mode_Id], [Mode_Parent_Sno] ,[Quantity]) VALUES (11,'BM',7,6)
INSERT INTO [dbo].[Travel_Occurs] ([Mode_Sno] ,[Mode_Id], [Mode_Parent_Sno] ,[Quantity]) VALUES (12,'AI',7,14)

Expected Result 

Kindly provide the query

ShanmugaRaj