Thanks for that explanation. As an SSIS beginner, that was very helpful. Unfortunately, I can't test it all the way through because the package keeps erroring out in the Preparation SQL Task in the Control Flow. This task was set up automatically when I ran the SSIS Import Export Wizard to create the package.
The task creates an interim table called Query that contains the column names relating to the Excel output file. In the properties, the Destination for the SQL Statement Connection parameter is DestinationConnectionExcel, which I created to handle the output of the SQL query. When I run the package, it fails on the "Create Table" statement stating that the table already exists, yet there seems to be no setting to delete or overwrite an existing table.
Do you know how I can get past this issue?