How to search for an ampersand in Elasticsearch?

Question

In Elasticsearch, how to search for a value with an ampersand? Tried:

http://localhost:9200/my_index/_search?q=name:"procter \u0026 gamble"

Answer 1

There are various ways but one way would be to declare your string as not_analyzed in your mapping (see below) and then search for the exact value that has been indexed.

curl -XPUT localhost:9200/tests -d '{
  "mappings": {
    "test": {
      "properties": {
        "name": {
          "type": "string",
          "fields": {
            "raw": {
              "type": "string",
              "index": "not_analyzed"
            }
          }
        }
      }
    }
  }
}'

Now we index a sample document:

curl -XPUT localhost:9200/tests/test/1 -d '{"name":"procter & gamble"}'

And finally, your search query will return the document you expect:

curl -XGET localhost:9200/tests/test/_search?q=name.raw:"procter %26 gamble"

UPDATE Here is another more involved way using an nGram tokenizer which will index all the possible tokens of length 2 to 20 (arbitrary choice) of your names.

curl -XPUT localhost:9200/tests -d '{
  "settings": {
    "analysis": {
      "analyzer": {
        "ngram_analyzer": {
          "tokenizer": "ngram_tokenizer",
          "filter": [
            "lowercase"
          ]
        }
      },
      "tokenizer": {
        "ngram_tokenizer": {
          "type": "nGram",
          "min_gram": 2,
          "max_gram": 20
        }
      }
    }
  },
  "mappings": {
    "test": {
      "properties": {
        "name": {
          "type": "string",
          "index_analyzer": "ngram_analyzer",
          "search_analyzer": "keyword"
        }
      }
    }
  }
}'

Then you can search for the exact name like before

curl -XGET localhost:9200/tests/test/_search?q=name:"procter %26 gamble"

Or simply by some token present in your name

curl -XGET localhost:9200/tests/test/_search?q=name:procter
curl -XGET localhost:9200/tests/test/_search?q=name:"procter %26"
curl -XGET localhost:9200/tests/test/_search?q=name:gamble