This is a coding example working on Caché 2018.1.3 and IRIS 2020.2 It will not be kept in synch with new versions It is also NOT serviced by InterSystems Support !
The full story is available here https://community.intersystems.com/post/light-weight-excel-download
But here's the light weight export to EXCEL.
Good old CSP is well equipped to produce HTML tables accepted from EXCEL as input. With modern Browsers you don't even need and tags. So the required code around your SQL result set is really slim. And you are free to add any formatting you need either by HTML or in SQL.
The final trick to move your table from browser to EXCEL: In the method OnPreHTTP inherited from %CSP.Page you set %response.ContentType="application/vnd.ms-excel"
Now when you call the class with your browser you get asked to open or to save it. Next , because the extenison is .cls you get asked for the program to open it. like this: https://raw.githubusercontent.com/rcemper/Light-weight-EXCEL-download-ZPM/master/oxls.jpg
And if you select EXCEL (or any compatible tool) the table is ready for the user to work with it. as this: https://raw.githubusercontent.com/rcemper/Light-weight-EXCEL-download-ZPM/master/xls.jpg
This could be a slim solution for rater static SQL queries. Well suited to serve a wide distributed population of users.
Rather small size of code with simple structure
Now you will understand why I titled it "Light Weight"