to try and help out...I'll throw the following code into the conversation

it may or may not be appropriate...but hopefully OP will reply with some code that helps us understand.

USE [TEMPDB] -- safe place

GO

-- go and create some test data to play with

IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Location]') AND type in (N'U'))

DROP TABLE [dbo].[Location]

GO

CREATE TABLE [dbo].[Location](

[LocationID] [varchar](1) NULL

) ON [PRIMARY]

GO

INSERT INTO [dbo].[Location]([LocationID])

SELECT N'A' UNION ALL

SELECT N'B' UNION ALL

SELECT N'C' UNION ALL

SELECT N'D' UNION ALL

SELECT N'E'

IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Trips]') AND type in (N'U'))

DROP TABLE [dbo].[Trips]

GO

CREATE TABLE [dbo].[Trips](

[Origin] [varchar](1) NULL,

[Destnation] [varchar](1) NULL,

[Tonnage] [int] NULL

) ON [PRIMARY]

GO

INSERT INTO [dbo].[Trips]([Origin], [Destnation], [Tonnage])

SELECT N'A', N'B', 5 UNION ALL

SELECT N'A', N'D', 2 UNION ALL

SELECT N'B', N'A', 3 UNION ALL

SELECT N'B', N'E', 7 UNION ALL

SELECT N'B', N'A', 5 UNION ALL

SELECT N'B', N'D', 2 UNION ALL

SELECT N'C', N'A', 1 UNION ALL

SELECT N'C', N'A', 18 UNION ALL

SELECT N'D', N'C', 12 UNION ALL

SELECT N'D', N'A', 5 UNION ALL

SELECT N'D', N'E', 6 UNION ALL

SELECT N'A', N'B', 12 UNION ALL

SELECT N'D', N'C', 30 UNION ALL

SELECT N'E', N'D', 100 UNION ALL

SELECT N'D', N'E', 50 UNION ALL

SELECT N'E', N'C', 12 UNION ALL

SELECT N'E', N'A', 15

--do some work to start playing with

;WITH cte AS

(

SELECT A.LocationID AS Origin ,

B.LocationID AS Destination

FROM

Location A INNER JOIN Location B ON A.LocationID <> B.LocationID

)

SELECT CTE.Origin, CTE.Destination, SUM(COALESCE (Trips.Tonnage, 0)) AS TOTALS

FROM CTE LEFT OUTER JOIN

Trips ON CTE.Destination = Trips.Destnation AND CTE.Origin = Trips.Origin

GROUP BY CTE.Origin, CTE.Destination

HAVING (SUM(COALESCE (Trips.Tonnage, 0)) > 0)

ORDER BY CTE.Origin, CTE.Destination

edit to exclude zero tonnage trips