RavenDB 4 - Querying for NULL in Lucene

[Andrej Krivulčík]

Is it possible to query for NULL when using Lucene in RavenDB 4?

Using [[NULL_VALUE]] doesn't work anymore:

• from index 'DocsIndex' where lucene("StrVal", "StrVal:[[NULL_VALUE]]")
  
• Lucene.Net.QueryParsers.ParseException: Cannot parse 'StrVal:[[NULL_VALUE]]': Encountered " "]" "] "" at line 1, column 19.
  Was expecting one of:
      "TO" ...
      <RANGEIN_QUOTED> ...
      <RANGEIN_GOOP> ...

It would be useful for achieving this: https://groups.google.com/forum/#!topic/ravendb/5JVjUgWm6jw

[Oren Eini (Ayende Rahien)]

where exact(Name = 'NULL_VALUE')

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[Andrej Krivulčík]

This isn't lucene thought, is it? I need to boost the value of not null values. In 3.5 it used to be something like:

((*:* AND StrVal:[[NULL_VALUE]])^100) OR (StrVal:[[NULL_VALUE]])

and then .OrderByScore(), to have null values always last.

So I'm looking for ways to do something similar in RavenDB 4.

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[Andrej Krivulčík]

Sorry, I dropped a minus sign there, it should be:

((*:* AND -StrVal:[[NULL_VALUE]])^100) OR (StrVal:[[NULL_VALUE]])

[Oren Eini (Ayende Rahien)]

How about this?

        public class DocsIndex : AbstractIndexCreationTask<Doc>
        {
            public DocsIndex()
            {
                Map = docs =>
                    from doc in docs
                    select new
                    {
                        doc.Id,
                        doc.StrVal ?? "zzzz",
                        doc.IntVal ?? long.MaxValue
                    };
            }
        }

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[Andrej Krivulčík]

Well, this is something like using [[NULL_VALUE]], having a special value we'd need to boost using the lucene query. If querying NULL_VALUE is not possible in lucene queries, I'll have to resort to something similar.