First search query in Elasticsearch - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the simplest way to perform a search query in Elasticsearch?

Use the match_all query to retrieve all documents in an index.

beginner

What does the match query do in Elasticsearch?

It searches for documents that match the given text in a specific field, analyzing the text for relevance.

beginner

How do you specify the index to search in Elasticsearch?

You specify the index name in the URL path of the search request, for example: GET /my_index/_search.

beginner

What is the role of the query field in an Elasticsearch search request?

It defines the criteria for selecting documents, such as match, term, or match_all queries.

beginner

What is the default HTTP method used to perform a search query in Elasticsearch?

The default HTTP method is GET, but POST can also be used when sending a request body.

Which Elasticsearch query returns all documents in an index?

A match

B term

C match_all

D range

The match_all query returns every document without filtering.

How do you specify the index to search in Elasticsearch?

A In the HTTP headers

B In the request URL path

C Inside the query body

D In the response

The index is specified in the URL path, e.g., GET /index_name/_search.

What does the match query do?

A Searches for exact values only

B Filters documents by range

C Returns all documents

D Searches analyzed text for relevance

The match query analyzes text and finds relevant documents.

Which HTTP method is commonly used for Elasticsearch search requests?

A GET

B PUT

C DELETE

D PATCH

GET is the default method for search requests, though POST is also allowed.

Where do you put the search criteria in an Elasticsearch request?

A Inside the <code>query</code> field in the request body

B In the URL query parameters

C In the HTTP headers

D In the response body

Search criteria go inside the query field in the JSON request body.

Describe how to perform a basic search query in Elasticsearch to find all documents.

Think about the simplest query that returns everything.

Explain the difference between the match and match_all queries in Elasticsearch.

One returns everything, the other filters by text.

Practice

1.

What does a match query do in an Elasticsearch search?

easy

A. It finds documents where the specified field contains the search text.

B. It deletes documents matching the search text.

C. It updates documents with the search text.

D. It creates a new index with the search text.

Solution

1. Step 1: Understand the purpose of match query

   The match query is used to find documents where a field contains the given text.

2. Step 2: Differentiate from other operations

   Deleting, updating, or creating indexes are different Elasticsearch operations, not done by match.

3. Final Answer:

   It finds documents where the specified field contains the search text. -> Option A

4. Quick Check:

   match query = find documents [OK]

Hint: Match query searches text in fields, not modify data [OK]

Common Mistakes:

• Confusing search with delete or update operations
• Thinking match creates or modifies indexes
• Assuming match returns all documents regardless of content

2.

Which of the following is the correct syntax for a basic Elasticsearch match query to search for "apple" in the field "fruit"?

{
  "query": {
    "match": {
      "fruit": "apple"
    }
  }
}

easy

A. { "query": { "match": { "fruit": "apple" } } }

B. { "match": { "query": { "fruit": "apple" } } }

C. { "query": { "fruit": { "match": "apple" } } }

D. { "query": { "match": { "apple": "fruit" } } }

Solution

1. Step 1: Identify the correct JSON structure for a match query

   The correct structure places match inside query, with the field name as key and search text as value.

2. Step 2: Compare options to this structure

   { "query": { "match": { "fruit": "apple" } } } matches the correct syntax exactly. Others misplace keys or swap field and text.

3. Final Answer:

   { "query": { "match": { "fruit": "apple" } } } -> Option A

4. Quick Check:

   Correct JSON structure = { "query": { "match": { "fruit": "apple" } } } [OK]

Hint: Match query is inside query, field name as key, text as value [OK]

Common Mistakes:

• Swapping field name and search text
• Placing match outside query
• Using wrong nesting of JSON keys

3.

Given this Elasticsearch query, what will it search for?

{
  "query": {
    "match": {
      "title": "quick brown fox"
    }
  }
}

medium

A. Documents where the title field contains the exact phrase "quick brown fox".

B. Documents where the title field contains only the word "fox".

C. Documents where the title field is empty.

D. Documents where the title field contains any of the words "quick", "brown", or "fox".

Solution

1. Step 1: Understand how match query works with multiple words

   The match query analyzes the text and searches for documents containing any of the words, not necessarily the exact phrase.

2. Step 2: Compare options with this behavior

   Documents where the title field contains any of the words "quick", "brown", or "fox". correctly states it searches for any of the words. Documents where the title field contains the exact phrase "quick brown fox". is phrase match, which requires a different query type.

3. Final Answer:

   Documents where the title field contains any of the words "quick", "brown", or "fox". -> Option D

4. Quick Check:

   match = any word match [OK]

Hint: Match finds any word in text, not exact phrase [OK]

Common Mistakes:

• Thinking match does exact phrase search
• Assuming match finds only one word
• Confusing match with match_phrase query

4.

Identify the error in this Elasticsearch query:

{
  "query": {
    "match": {
      "content": apple
    }
  }
}

medium

A. The match query should be outside the query object.

B. The field name content should be in quotes.

C. The search text apple should be in quotes.

D. The query object is missing a closing brace.

Solution

1. Step 1: Check JSON syntax for values

   In JSON, string values must be enclosed in double quotes. Here, apple is unquoted.

2. Step 2: Verify other parts of the query

   The field name and braces are correctly quoted and closed. The match query is correctly inside query.

3. Final Answer:

   The search text apple should be in quotes. -> Option C

4. Quick Check:

   Strings need quotes in JSON [OK]

Hint: Always quote string values in JSON queries [OK]

Common Mistakes:

• Leaving string values unquoted
• Misplacing match outside query
• Forgetting closing braces

5.

You want to find documents where the field "description" contains the word "fresh" but only if the field "category" equals "fruit". Which Elasticsearch query correctly combines these conditions?

hard

A. { "query": { "match": { "description": "fresh" }, "match": { "category": "fruit" } } }

B. { "query": { "bool": { "must": [ { "match": { "description": "fresh" } }, { "match": { "category": "fruit" } } ] } } }

C. { "query": { "term": { "description": "fresh" }, "term": { "category": "fruit" } } }

D. { "query": { "match": { "description": "fresh fruit" } } }

Solution

1. Step 1: Understand combining multiple conditions in Elasticsearch

   To require both conditions, use a bool query with must array containing each match query.

2. Step 2: Evaluate each option's structure

   { "query": { "bool": { "must": [ { "match": { "description": "fresh" } }, { "match": { "category": "fruit" } } ] } } } correctly uses bool with must for both matches. { "query": { "match": { "description": "fresh fruit" } } } searches combined text in one field. Options A and C have invalid JSON or incorrect query structure.

3. Final Answer:

   { "query": { "bool": { "must": [ { "match": { "description": "fresh" } }, { "match": { "category": "fruit" } } ] } } } -> Option B

4. Quick Check:

   Use bool must to combine queries [OK]

Hint: Use bool must array to combine multiple match queries [OK]

Common Mistakes:

• Combining terms incorrectly in one match
• Using invalid JSON with repeated keys
• Not using bool query for multiple conditions