Range query in Elasticsearch - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a range query in Elasticsearch?

A range query finds documents where a field's value falls within a specified range, like numbers, dates, or strings.

beginner

Which operators can you use in a range query?

You can use gt (greater than), gte (greater than or equal), lt (less than), and lte (less than or equal).

beginner

Show a simple example of a range query to find documents with age between 20 and 30.

{
  "query": {
    "range": {
      "age": {
        "gte": 20,
        "lte": 30
      }
    }
  }
}

beginner

Can range queries be used on date fields in Elasticsearch?

Yes! Range queries work well on date fields to find documents within specific time periods.

beginner

What happens if you use only one operator in a range query, like gt?

The query finds all documents where the field's value is greater than the given value, with no upper limit.

Which operator finds documents with values less than or equal to a number?

A lt

B gte

C lte

D gt

The lte operator means 'less than or equal to'.

What does this range query do? { "range": { "price": { "gt": 100 } } }

A Finds documents with price greater than 100

B Finds documents with price less than 100

C Finds documents with price equal to 100

D Finds documents with price between 0 and 100

The gt operator means 'greater than', so it finds prices above 100.

Can range queries be used on text fields?

A Yes, on any field

B Only on keyword fields

C No, only numeric and date fields

D Only on analyzed text fields

Range queries work on keyword fields (exact values), not on analyzed text fields.

Which operator includes the boundary value in the range?

A gt

B none

C lt

D gte

gte means 'greater than or equal to', so it includes the boundary.

What is the result if you omit all operators in a range query?

A It causes an error

B It returns all documents

C It returns no documents

D It defaults to gt:0

A range query needs at least one operator; otherwise, it is invalid and causes an error.

Explain how to use a range query to find documents with a date field between two dates.

Think about how to specify start and end dates with operators.

Describe the difference between the operators gt and gte in a range query.

Focus on whether the boundary value is included or not.

Practice

1. What does a range query in Elasticsearch do?

easy

A. It updates documents with new values.

B. It counts the total number of documents in the index.

C. It finds documents with field values between specified limits.

D. It deletes documents matching a condition.

Solution

1. Step 1: Understand the purpose of range query

   A range query filters documents where a field's value falls within given boundaries like greater than or less than.

2. Step 2: Compare with other query types

   Counting, updating, or deleting documents are different operations, not done by range queries.

3. Final Answer:

   It finds documents with field values between specified limits. -> Option C

4. Quick Check:

   Range query = filter by value limits [OK]

Hint: Range query filters values between limits using gte, lte, gt, lt [OK]

Common Mistakes:

• Confusing range query with count or update operations
• Thinking range query modifies data
• Assuming range query deletes documents

2. Which of the following is the correct syntax for a range query filtering documents where price is greater than or equal to 10 and less than 20?

easy

A. { "range": { "price": { "gte": 10, "lte": 20 } } }

B. { "range": { "price": { "gt": 10, "lte": 20 } } }

C. { "range": { "price": { "gt": 10, "lt": 20 } } }

D. { "range": { "price": { "gte": 10, "lt": 20 } } }

Solution

1. Step 1: Identify the boundary conditions

   The question asks for price >= 10 and price < 20, which means gte:10 and lt:20.

2. Step 2: Match syntax with conditions

   { "range": { "price": { "gte": 10, "lt": 20 } } } uses gte and lt correctly matching the condition.

3. Final Answer:

   { "range": { "price": { "gte": 10, "lt": 20 } } } -> Option D

4. Quick Check:

   gte=10 and lt=20 syntax = { "range": { "price": { "gte": 10, "lt": 20 } } } [OK]

Hint: Match gte/gt and lte/lt exactly to the question limits [OK]

Common Mistakes:

• Mixing up gte with gt or lte with lt
• Using wrong operators for boundaries
• Syntax errors like missing braces

3. Given this Elasticsearch query, what documents will it match?

{ "query": { "range": { "age": { "gt": 30, "lte": 40 } } } }

medium

A. Documents where age is greater than 30 and less than or equal to 40.

B. Documents where age is between 30 and 40 inclusive.

C. Documents where age is greater than or equal to 30 and less than 40.

D. Documents where age is exactly 30 or 40.

Solution

1. Step 1: Interpret the range operators

   "gt": 30 means age > 30 (not including 30), "lte": 40 means age ≤ 40 (including 40).

2. Step 2: Understand the matching documents

   Documents with age greater than 30 and less than or equal to 40 will match.

3. Final Answer:

   Documents where age is greater than 30 and less than or equal to 40. -> Option A

4. Quick Check:

   gt=30 and lte=40 means age >30 and ≤ 40 [OK]

Hint: Remember gt excludes boundary, lte includes boundary [OK]

Common Mistakes:

• Confusing gt with gte or lte with lt
• Assuming boundaries are inclusive when they are not
• Misreading the query operators

4. Identify the error in this range query that tries to find documents with date between '2023-01-01' and '2023-12-31':

{ "range": { "date": { "gte": "2023-01-01", "lt": "2023-12-31" } }

medium

A. The field name 'date' must be inside a 'query' object.

B. The query is missing a closing brace '}' at the end.

C. The range query cannot use 'gte' and 'lt' together.

D. The date format is incorrect; it should be timestamps.

Solution

1. Step 1: Check JSON syntax

   The query is missing the final closing brace '}' to close the outer object.

2. Step 2: Validate other parts

   Date format as string is valid in Elasticsearch; using gte and lt together is allowed; 'date' field can be directly inside range.

3. Final Answer:

   The query is missing a closing brace '}' at the end. -> Option B

4. Quick Check:

   Missing closing brace = syntax error [OK]

Hint: Always check JSON braces and commas carefully [OK]

Common Mistakes:

• Forgetting to close JSON objects
• Assuming date strings must be timestamps
• Thinking gte and lt cannot be combined

5. You want to filter products priced between 50 and 100 inclusive, but exclude those exactly priced at 75. Which Elasticsearch query correctly applies this logic?

hard

A. { "bool": { "must": { "range": { "price": { "gte": 50, "lte": 100 } } }, "must_not": { "term": { "price": 75 } } } }

B. { "range": { "price": { "gte": 50, "lte": 100, "neq": 75 } } }

C. { "range": { "price": { "gt": 50, "lt": 100 } }, "must_not": { "term": { "price": 75 } } }

D. { "bool": { "should": { "range": { "price": { "gte": 50, "lte": 100 } } }, "must_not": { "term": { "price": 75 } } } }

Solution

1. Step 1: Understand the filtering requirements

   We want prices between 50 and 100 inclusive, so gte:50 and lte:100 in a range query.

2. Step 2: Exclude price exactly 75

   Use a bool query with must for range and must_not for term price=75 to exclude it.

3. Step 3: Check options

   { "bool": { "must": { "range": { "price": { "gte": 50, "lte": 100 } } }, "must_not": { "term": { "price": 75 } } } } uses bool with must range and must_not term correctly. { "range": { "price": { "gte": 50, "lte": 100, "neq": 75 } } } uses invalid 'neq'. { "range": { "price": { "gt": 50, "lt": 100 } }, "must_not": { "term": { "price": 75 } } } misses bool wrapper. { "bool": { "should": { "range": { "price": { "gte": 50, "lte": 100 } } }, "must_not": { "term": { "price": 75 } } } } uses should which is incorrect here.

4. Final Answer:

   { "bool": { "must": { "range": { "price": { "gte": 50, "lte": 100 } } }, "must_not": { "term": { "price": 75 } } } } -> Option A

5. Quick Check:

   Use bool must + must_not for inclusive range excluding a value [OK]

Hint: Use bool must for range and must_not to exclude values [OK]

Common Mistakes:

• Using invalid operators like 'neq' in range
• Not wrapping queries in bool for combining conditions
• Using should instead of must for filtering