How to query for maximum field value in Lucene.Net?

Question

We want to be able to return a single document with a maximum value for a particular field. A typical example would be,

max(date_time_field:*)

which returns the latest document in the index.

Is there any support for something like this in Lucene.Net?

Answer 1

I'm not sure how you are querying your index, but you can certainly order by the field in question, and then simply take the top document:

var sortBy = new Sort(new SortField("date_time_field", SortField.DOUBLE, true));
var hits = ... IndexSearcher.Search(query, null, 1, sortBy));

...

var doc = searcher.IndexSearcher.Doc(hits.ScoreDocs[0]);