Hello @oliviergroux ,
You can query all your data from this orders schema and then add an enrichment after this.
In the enrichment add these two columns product id and the customer Id. Check the checkbox which says groupBy for product id column and then in the recipient column
Something like this

Then after running the query you will get the output where you will have the total number of orders against a product like this:

Then you can again enrich this data on the basis of product id with the original table to get the desired output. I have added an additional column of no orders.

Let me know if that helps.
Thanks