I have a collection of documents where each document looks like
{
"_id": ... ,
"Author": ...,
"Content": ....,
"DateTime": ...
}
I would like to issue one query to the collection so that I get in response the oldest document from each author. I am considering using a terms aggregation but when I do that I get a list of buckets, being the unique Author values, telling me nothing about which of their documents is the oldest. Furthermore, that approach requires a subsequent call to ES, which is undesirable.
Any advice you could offer would be greatly appreciated. Thanks.