Querystring search on array elements in Elastic Search

Question

I'm trying to learn elasticsearch with a simple example application, that lists quotations associated with people. The example mapping might look like:

{ 
  "people" : {
    "properties" : {
      "name" : { "type" : "string"},
      "quotations" : { "type" : "string" }
    }
  }
}

Some example data might look like:

{ "name" : "Mr A",
  "quotations" : [ "quotation one, this and that and these"
                 , "quotation two, those and that"]
}

{ "name" : "Mr B",
  "quotations" : [ "quotation three, this and that"
                 , "quotation four, those and these"]
}

I would like to be able to use the querystring api on individual quotations, and return the people who match. For instance, I might want to find people who have a quotation that contains (this AND these) - which should return "Mr A" but not "Mr B", and so on. How can I achieve this?

EDIT1:

Andrei's answer below seems to work, with data values now looking like:

{"name":"Mr A","quotations":[{"value" : "quotation one, this and that and these"}, {"value" : "quotation two, those and that"}]}

However, I can't seem to get a query_string query to work. The following produces no results:

{
  "query": {
    "nested": {
      "path": "quotations",
      "query": {
        "query_string": {
            "default_field": "quotations",
            "query": "quotations.value:this AND these"
        }
      }
    }
  }
}

Is there a way to get a query_string query working with a nested object?

Edit2: Yes it is, see Andrei's answer.

Andrei Stefan · Accepted Answer · 2014-10-09 13:33:13Z

42

For that requirement to be achieved, you need to look at nested objects, not to query a flattened list of values but individual values from that nested object. For example:

{
  "mappings": {
    "people": {
      "properties": {
        "name": {
          "type": "string"
        },
        "quotations": {
          "type": "nested",
          "properties": {
            "value": {
              "type": "string"
            }
          }
        }
      }
    }
  }
}

Values:

{"name":"Mr A","quotations":[{"value": "quotation one, this and that and these"}, {"value": "quotation two, those and that"}]}
{"name":"Mr B","quotations":[{"value": "quotation three, this and that"}, {"value": "quotation four, those and these"}]}

Query:

{
  "query": {
    "nested": {
      "path": "quotations",
      "query": {
        "bool": {
          "must": [
            { "match": {"quotations.value": "this"}},
            { "match": {"quotations.value": "these"}}
          ]
        }
      }
    }
  }
}

edited Oct 9, 2014 at 13:33

answered Oct 8, 2014 at 15:04

Andrei Stefan

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6 Comments

oneway Over a year ago

I had to change the Values to look like:

{"name":"Mr A","quotations":[{"value" : "quotation one, this and that and these"}, {"value" : "quotation two, those and that"}]}

, but this worked. Is there any way to use a QueryStringQuery with this? I tried using one (just replacing the bool with query_string), and it didn't seem to work.

Andrei Stefan Over a year ago

You're right. Now I noticed that I copy-pasted the wrong values, even though I tested with the correct ones (the ones you mentioned).

Andrei Stefan Over a year ago

Try this:

{   "query": {     "nested": {       "path": "quotations",       "query": {         "query_string": {           "default_field": "quotations.value",           "query": "this AND these"         }       }     }   } }

oneway Over a year ago

Ah, I just had default_field as quotations. This works, many thanks!

salsbury Over a year ago

As an update for ElasticSearch 6.2 (at least), an error occurs when you try to use the string type in a mappint. The error from running this is No handler for type [string] declared on field [value]. Similar valid types are now text and keyword (elastic.co/guide/en/elasticsearch/reference/current/…).

|

techfly · Accepted Answer · 2020-11-06 15:27:56Z

Unfortunately there is no good way to do that. https://web.archive.org/web/20141021073225/http://www.elasticsearch.org/guide/en/elasticsearch/guide/current/complex-core-fields.html

When you get a document back from Elasticsearch, any arrays will be in the same order as when you indexed the document. The _source field that you get back contains exactly the same JSON document that you indexed.

However, arrays are indexed — made searchable — as multi-value fields, which are unordered. At search time you can’t refer to “the first element” or “the last element”. Rather think of an array as a bag of values.

In other words, it is always considering all values in the array.

This will return only Mr A

{
  "query": {
    "match": {
      "quotations": {
        "query": "quotation one",
        "operator": "AND"
      }
    }
  }
}

But this will return both Mr A & Mr B:

{
  "query": {
    "match": {
      "quotations": {
        "query": "this these",
        "operator": "AND"
      }
    }
  }
}

mjassani · Accepted Answer · 2018-09-17 01:23:28Z

0

If scripting is enabled, this should work:

"script": {
   "inline": "for(element in _source.quotations) { if(element == 'this' && element == 'these') {return true;} }; return false;"
 }

answered Sep 17, 2018 at 1:23

mjassani

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