Master Elasticsearch Queries: From match_all to Fuzzy Search

Elasticsearch Overview

Elasticsearch provides a powerful way to retrieve data using Query DSL, a JSON‑based query language accessed via RESTful endpoints.

Elasticsearch Query Syntax

GET /<index_name>/_search {
  // JSON request body
}

Common Elasticsearch Queries

1. Match All Query

Retrieves all documents without any conditions.

GET /mikechen/_search {
  "query": {
    "match_all": {}
  }
}

2. Term Query

Exact match on a single term; the query term is not analyzed.

GET /mikechen/_search {
  "query": {
    "term": {
      "title": "love China"
    }
  }
}

3. Terms Query

Matches any of the specified terms, similar to SQL IN.

{
  "query": {
    "terms": {
      "keyword": ["mikechen", "互联网架构"]
    }
  }
}

4. Range Query

Searches for documents where a field falls within a specified range.

{
  "query": {
    "range": {
      "age": {
        "gte": 18,
        "lt": 30
      }
    }
  }
}

5. Prefix Query

Finds documents whose field values start with a given prefix.

GET /user/_search {
  "query": {
    "prefix": {
      "name": "mikechen"
    }
  }
}

6. Wildcard Query

Uses * for zero or more characters and ? for a single character.

GET /user/_search {
  "query": {
    "wildcard": {
      "name": "mikechen*"
    }
  }
}

7. Regexp Query

Applies a regular expression to match field values.

POST /mikechen/book/_search {
  "query": {
    "regexp": {
      "authors": "t[a-z]*y"
    }
  }
}

8. Bool (Compound) Query

Combines multiple queries using four clauses: must, should, must_not, and filter.

GET /books/_search {
  "query": {
    "bool": {
      "must": [
        { "term": { "name": { "value": "java" } } }
      ],
      "should": [
        { "match": { "info": "mikechen互联网架构" } }
      ]
    }
  }
}

9. Fuzzy Query

Handles misspellings by allowing a specified edit distance.

GET /blogs_index/_search {
  "query": {
    "fuzzy": {
      "author": {
        "value": "方财兄",
        "fuzziness": 1,
        "prefix_length": 1,
        "max_expansions": 100
      }
    }
  }
}

These examples demonstrate how to construct a variety of Elasticsearch queries to meet different search requirements.