Elasticsearch Mastering the Use of Elasticsearch AND and OR Operators

By Opster Team

Updated: Nov 5, 2023

| 2 min read

Quick links

• Overview
• Using the AND Operator in Elasticsearch
• Using the OR Operator in Elasticsearch
• Combining AND and OR Operators
• Understanding the Impact of AND and OR Operators on Relevance Scoring
• Conclusion

Overview

Elasticsearch provides a rich query language that allows for complex data exploration. Among the most commonly used elements of this language are the AND and OR operators. These operators are used to combine multiple search queries, allowing for more precise and targeted results.

The AND operator is used to combine multiple queries, where all conditions must be met for a document to be included in the results. On the other hand, the OR operator is used to combine multiple queries, where at least one condition must be met for a document to be included in the results.

Let’s delve deeper into the usage of these operators in Elasticsearch.

Using the AND Operator in Elasticsearch

The AND operator is used in Elasticsearch to combine multiple search conditions. All conditions must be met for a document to be included in the results. Here is an example of how to use the AND operator in a query_string query:

GET /_search
{
  "query": {
    "query_string": {
      "query": "field1:value1 AND field2:value2"
    }
  }
}

In this example, the query will return documents where `field1` matches `value1` AND `field2` matches `value2`. It is also semantically equivalent to perform the same AND query using a `bool/must` query with two `match` clauses, as shown below:

GET /_search
{
  "query": {
    "bool": {
      "must": [
        { "match": { "field1": "value1" }},
        { "match": { "field2": "value2" }}
      ]
    }
  }
}

Using the OR Operator in Elasticsearch

The OR operator is used in Elasticsearch to combine multiple search conditions. At least one condition must be met for a document to be included in the results. Here is an example of how to use the OR operator in a query_string query:

GET /_search
{
  "query": {
    "query_string": {
      "query": "field1:value1 OR field2:value2"
    }
  }
}

In this example, the query will return documents where `field1` matches `value1` OR `field2` matches `value2`. As shown earlier, it is also possible to perform the same OR query using a `bool/should` query with two `match` clauses, as shown below:

GET /_search
{
  "query": {
    "bool": {
      "should": [
        { "match": { "field1": "value1" }},
        { "match": { "field2": "value2" }}
      ],
      "minimum_should_match": 1
    }
  }
}

Combining AND and OR Operators

Elasticsearch allows for the combination of AND and OR operators in a single query, enabling the creation of complex search conditions. Here is an example with a query_string query:

GET /_search
{
  "query": {
    "query_string": {
      "query": "field1:value1 AND field2:value2 AND (field3:value3 OR field4:value4)"
    }
  }
}

In this example, the query will return documents where (`field1` matches `value1` AND `field2` matches `value2`) AND (`field3` matches `value3` OR `field4` matches `value4`).

Using bool queries, we can create the same kind of AND/OR conditions using a combination of `must` and `should` clauses, as shown below:

GET /_search
{
  "query": {
    "bool": {
      "must": [
        { "match": { "field1": "value1" }},
        { "match": { "field2": "value2" }}
      ],
      "should": [
        { "match": { "field3": "value3" }},
        { "match": { "field4": "value4" }}
      ],
      "minimum_should_match": 1
    }
  }
}

Understanding the Impact of AND and OR Operators on Relevance Scoring

The use of AND and OR operators in Elasticsearch queries can impact the relevance scoring of the results. When using the AND operator, the score is calculated based on the sum of the scores of the individual queries. When using the OR operator, the score is calculated based on the maximum score of the individual queries.

Conclusion

In conclusion, the AND and OR operators are powerful tools in Elasticsearch that allow for the creation of complex search conditions. By understanding how to use these operators, you can create more precise and targeted search queries.