How to search for a part of a word with ElasticSearch

I'm using nGram, too. I use standard tokenizer and nGram just as a filter. Here is my setup:

{
  "index": {
    "index": "my_idx",
    "type": "my_type",
    "analysis": {
      "index_analyzer": {
        "my_index_analyzer": {
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
            "lowercase",
            "mynGram"
          ]
        }
      },
      "search_analyzer": {
        "my_search_analyzer": {
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
            "standard",
            "lowercase",
            "mynGram"
          ]
        }
      },
      "filter": {
        "mynGram": {
          "type": "nGram",
          "min_gram": 2,
          "max_gram": 50
        }
      }
    }
  }
}

Let's you find word parts up to 50 letters. Adjust the max_gram as you need. In german words can get really big, so I set it to a high value.

Searching with leading and trailing wildcards is going to be extremely slow on a large index. If you want to be able to search by word prefix, remove leading wildcard. If you really need to find a substring in a middle of a word, you would be better of using ngram tokenizer.

I think there's no need to change any mapping. Try to use query_string, it's perfect. All scenarios will work with default standard analyzer:

We have data:

{"_id" : "1","name" : "John Doeman","function" : "Janitor"}
{"_id" : "2","name" : "Jane Doewoman","function" : "Teacher"}

Scenario 1:

{"query": {
    "query_string" : {"default_field" : "name", "query" : "*Doe*"}
} }

Response:

{"_id" : "1","name" : "John Doeman","function" : "Janitor"}
{"_id" : "2","name" : "Jane Doewoman","function" : "Teacher"}

Scenario 2:

{"query": {
    "query_string" : {"default_field" : "name", "query" : "*Jan*"}
} }

Response:

{"_id" : "1","name" : "John Doeman","function" : "Janitor"}

Scenario 3:

{"query": {
    "query_string" : {"default_field" : "name", "query" : "*oh* *oe*"}
} }

Response:

{"_id" : "1","name" : "John Doeman","function" : "Janitor"}
{"_id" : "2","name" : "Jane Doewoman","function" : "Teacher"}

EDIT - Same implementation with spring data elastic search https://stackoverflow.com/a/43579948/2357869

One more explanation how query_string is better than others https://stackoverflow.com/a/43321606/2357869

without changing your index mappings you could do a simple prefix query that will do partial searches like you are hoping for

ie.

{
  "query": { 
    "prefix" : { "name" : "Doe" }
  }
}

https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-prefix-query.html

How to search for a part of a word with ElasticSearch

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