Thank you for your response.
I tried your suggestion and the number of records is now correct as per the $Rows measure.
However, there does seem to be some strange behaviour.
When I now build a table box showing the records for Trans, it now shows multiple records where previoulsy there was only one! So the behaviour seems to have reversed.
The problem seems to be caused by teh ActualTime fiedl ie in the Table Box it shows every possible ActualTime value for each record, rather than the ActualTime for that record.
It would be of great help to me if you could explian your solution? I do not have a lot of experience with scripting. For instance, I do not understand why you are creating new fields for TargetTime and ActualTime? Or how you can load the formula for Delta using these field names when they have not already been identified in the script? Is there something I do not understand about the order of the script?
Regards and thanks for your help.
PS - I added DISTINCT to the LOAD in the second JOIN in my script and it seems to work (sort of). Does that give you any clues?
Yes, I have created the RouteCode field in the Trans table before attempting the joins.
However, the RouteCode field values are not unique ie there are multiple instances of the same RouteCode for different records in the Trans table.
What I am trying to do in the Trans table is add the appropriate TargTime for each RouteCode, which is stored in the TripMatrix table.
In the second Left Join, I am tring to calculate the difference between the TargTime (which I assume is now present for each record in the Trans table) and the actual time (TIME_m) which is calculated during the original load of the Trans table.