Exact Match

Elastic Stack Elasticsearch
1

Hey all

How could I in elastic search do my search in such a way that only if both fields given are a match will a result be given? Like an AND statement.

Here is what I am trying to do (minified code):

var searchResult = searchClient.Search<Log>(s => 
 .Index(uriIndex)
 .Query(q =>
      q.ConstantScore(cs => 
           .Filter(f => f
                 .Term(t => t.Status, _status)
           )
      ) &&
      q.MultiMatch(mm => mm
            .Query(_phrase)
                  .Fields(fs => fs
                       .Field(f => f.Data)
                  )
             ) 
      )
 );

Regards

2

There are several ways to implement an "AND" statement.
You're using the multi_match query. If you want only hits where the search term appears in 2 fields, you can use the "minimum_should_match" parameter (set to 2).

You could also build a bool-query with 2 must clauses.

3

Thanks for the quick response.

The multi_match I am using as I want to search multiple fields. I just only included the one so as not to make the question to long.

Regarding the bool-query, is something like this on the right track?

q.Bool(b => b
       .Must(m => m
           .Term(t => t
                  .Field(f => f.Status)
                  .Value(_status)
            )
       )
       .Must(m => m
             .Term(t => t
                      .Field(f => f.data)
                       .Value(_term)
              )
       )

)

I will take a look into the minimum_should_match.

4

Yes that looks good :slight_smile:

A "multi_match" query over 2 fields with the "minimum_should_match" parameter set to 2 in your case is equivalent to a bool-query with 2 must-clauses.

5

Sweet :slight_smile: Thank you

6

Does the must-clause run concurrently? I am getting 3 results for the _status check, _term check and then _status && _term check, not just the _status && _term check. Or so it seems.

7

What I ended up doing was to have a single must-clause and in that I did my checks to make the following (X AND (Y OR X)) statement.

In ElasticSearch it looks like the following:

                .Bool(b => b
                    .Must(m =>
                        m.Match(ma => ma
                            .Query(_status)
                            .Field(f => f.Status)
                        ) &&
                        m.Bool(b2 => b2
                            .Should(sh => sh
                                .MultiMatch(mm => mm
                                    .Query(_phrase)
                                    .Fields(fs => fs
                                         .Field(f => f.Data)
                                       // Rest of my fields
                                    )
                                ) ||
                                q.Terms(ts => ts.Field(f => f.Data).Terms(_terms)) ||
                                // The rest of my fields
                                 )
                             )
                         )
                   )

This may not be the best way to do it, but it is what I have working at the moment. As I work with ElasticSearch more and the scope of the project changes, this will improve in the future.

Regards

8

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