Elasticsearch Array Intersect Query

Question

I'm trying to filter results based on whether an array field has at least one element from another set.

I have a field containing an array of strings eg:

_source: {
...
keywords: [
"Data Science",
"Chemistry",
"Biology",
"Computer Science",
"Economics"
]
}

I'd like to filter the results such that keywords contain at least one of a list of values, eg:

> ["History","Biology"] # would return the above document
> ["History","Geography"] # would not

It doesn't really matter how many it contains, just that it matches at least one of them.

I tried the terms query, but that does not give me any results

Answer 1

The terms query is an OR-query by default so the following will match

{
  "query": {
    "terms": {
      "keywords": [
        "Chemistry",
        "Geography"
      ]
    }
  }
}

if your condition such that keywords contain at least one is to be satisfied.

---

Now, if the requirement is to use an AND query (if one more more do not match, return null), you can use a bool-must query

{
  "query": {
    "bool": {
      "must": [
        {
          "term": {
            "keywords": {
              "value": "Chemistry"
            }
          }
        },
        {
          "term": {
            "keywords": {
              "value": "Geography"
            }
          }
        }
      ]
    }
  }
}

Depending on the mapping you may need to append .keyword to the field in question.