Exact (not substring) matching in Elasticsearch

Question

{"query":{ "match" : { "content" : "2" } }} matches all the documents whole content contains the number 2, however I would like the content to be exactly 2, no more no less - think of my requirement in a spirit of Java's String.equals.

Similarly for the second query I would like to match when the document's content is exactly '3 3' and nothing more or less. {"query":{ "match" : { "content" : "3 3" } }}

How could I do exact (String.equals) matching in Elasticsearch?

Answer 1

Without seeing your index type mapping and sample data, it's hard to answer this directly - but I'll try.

Offhand, I'd say this is similar to this answer here (https://stackoverflow.com/a/12867852/382774), where you simply set the content field's index option to not_analyzed in your mapping:

"url" : {
    "type" : "string", 
    "index" : "not_analyzed"
}

Edit: I wasn't clear enough with my original answer, shown above. I did not mean to imply that you should add the example code to your query, I meant that you need to specify in your index type mapping that the url field is of type string and it is indexed but not analyzed (not_analyzed).

This tells Elasticsearch to not bother analyzing (tokenizing or token filtering) the field when you're indexing your documents - just store it in the index as it exists in the document. For more information on mappings, see http://www.elasticsearch.org/guide/reference/mapping/ for an intro and http://www.elasticsearch.org/guide/reference/mapping/core-types/ for specifics on not_analyzed (tip: search for it on that page).

Update:

Official doc tells us that in a new version of Elastic search you can't define variable as "not_analyzed", instead of this you should use "keyword".

For the old version elastic:

{
  "foo": {
    "type" "string",
    "index": "not_analyzed"
  }

}

For new version:

{
  "foo": {
    "type" "keyword",
    "index": true
  }
}

Note that this functionality (keyword type) are from elastic 5.0 and backward compatibility layer is removed from Elasticsearch 6.0 release.

Answer 2

Official Doc

You should use filter instead of match.

{
"query" : {
    "constant_score" : { 
        "filter" : {
            "term" : { 
                "content" : 2
            }
        }
    }
}

And you got docs whose content is exact 2, instead of 20 or 2.1