Range query in Elasticsearch - Mini Project: Build & Apply

Range query

📖 Scenario: You have a collection of products in an online store. Each product has a price. You want to find products within a certain price range.

🎯 Goal: Build an Elasticsearch range query to find products priced between 50 and 150.

📋 What You'll Learn

Create an Elasticsearch index mapping with a price field of type float.

Add a configuration variable for the price range minimum and maximum.

Write a range query using the range keyword with gte and lte for the price field.

Print the final query JSON.

💡 Why This Matters

🌍 Real World

Range queries are used in search engines to filter results by numbers like price, date, or ratings.

💼 Career

Knowing how to write range queries is important for roles involving search, data filtering, and Elasticsearch administration.

1

Create index mapping with price field

Create a variable called index_mapping and assign it a JSON object with a mappings key. Inside mappings, add properties with a price field of type float.

Elasticsearch

# Create the index mapping with price field
# Your code here

Hint

Use a dictionary with keys mappings and properties. Set price type to float.

2

Set price range variables

Create two variables called min_price and max_price and set them to 50 and 150 respectively.

Elasticsearch

index_mapping = {
    "mappings": {
        "properties": {
            "price": {"type": "float"}
        }
    }
}
# Set min_price and max_price variables
# Your code here

Hint

Assign 50 to min_price and 150 to max_price.

3

Create the range query

Create a variable called range_query and assign it a JSON object with a query key. Inside query, use range on the price field with gte set to min_price and lte set to max_price.

Elasticsearch

index_mapping = {
    "mappings": {
        "properties": {
            "price": {"type": "float"}
        }
    }
}
min_price = 50
max_price = 150
# Create the range query using min_price and max_price
# Your code here

Hint

Use the range keyword inside query with gte and lte set to the variables.

4

Print the range query

Write a print statement to display the range_query variable.

Elasticsearch

index_mapping = {
    "mappings": {
        "properties": {
            "price": {"type": "float"}
        }
    }
}
min_price = 50
max_price = 150
range_query = {
    "query": {
        "range": {
            "price": {
                "gte": min_price,
                "lte": max_price
            }
        }
    }
}
# Print the range_query variable
# Your code here

Hint

Use print(range_query) to show the query.

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