Elasticsearch is a powerful search engine that offers a flexible and efficient way to query and analyze large volumes of data. Query DSL (Domain Specific Language) is a feature of Elasticsearch that allows you to define complex queries to retrieve specific data from your Elasticsearch index.

One common requirement in search queries is to have multiple conditions connected with an OR operator. In this article, we will explore different ways to build an OR condition in Elasticsearch Query DSL.

Method 1: Using the bool query

The bool query is a versatile and commonly used query type in Elasticsearch. It allows you to combine multiple query clauses, such as match, term, or range, using logical operators like AND and OR.

To build an OR condition using the bool query, you can use the should parameter. The should parameter allows you to specify multiple query clauses that will be evaluated independently. If any of the clauses match, the document will be considered a match.

Here’s an example of how to build an OR condition using the bool query:

{
  "query": {
    "bool": {
      "should": [
        {
          "match": {
            "field1": "value1"
          }
        },
        {
          "match": {
            "field2": "value2"
          }
        }
      ]
    }
  }
}

In the above example, documents will be considered a match if either “field1” is equal to “value1” or “field2” is equal to “value2”.

Method 2: Using the constant_score query

Another way to build an OR condition is by using the constant_score query. This query type wraps another query and returns a constant score for all documents that match the inner query.

To build an OR condition using the constant_score query, you can use the should parameter along with a bool query inside the constant_score query.

Here’s an example of how to build an OR condition using the constant_score query:

{
  "query": {
    "constant_score": {
      "filter": {
        "bool": {
          "should": [
            {
              "match": {
                "field1": "value1"
              }
            },
            {
              "match": {
                "field2": "value2"
              }
            }
          ]
        }
      }
    }
  }
}

In the above example, the constant_score query is used to wrap the bool query with the OR conditions. Documents that match either “field1” equal to “value1” or “field2” equal to “value2” will receive a constant score.

Conclusion

In this article, we have explored two different methods to build an OR condition in Elasticsearch Query DSL. The first method uses the bool query with the should parameter, allowing you to combine multiple query clauses with an OR operator. The second method involves using the constant_score query to wrap a bool query and return a constant score for matched documents.

By understanding these techniques, you can effectively build complex queries to retrieve the desired data from your Elasticsearch index.

本文来自极简博客，作者：黑暗征服者，转载请注明原文链接：How to Build an OR Condition in Elasticsearch Query DSL