How to customize the export of an Aggregate to Excel?
1. Is there a way to change the labels? In this case, multiple tables being joined have the same field called Label.
2. Any way to force the ordering? I’d like to have D, E, F first then A, B, C then G.
The way to give the columns, customized labels is to use a structure on an advance query. Then, what you define on the structure attribute Label will be the correspondent Column name on the exported Excel.
In the screenshot above you can see an example. You don't need to use alias, just define on the Structure Attribute, the label that you want to see on the columns.
Then when you export to the Excel, you'll see the result you wanted.
Then, as you said, you can freely change the order of your output on the advance query (just remember to always match them with the attributes order on your structure).