Bool query in depth in Elasticsearch - Mini Project: Build & Apply

Bool query in depth

📖 Scenario: You are building a search feature for a bookstore website. You want to find books based on multiple conditions like genre, author, and price range.

🎯 Goal: Create an Elasticsearch bool query that combines multiple conditions to find books that match all or some of the criteria.

📋 What You'll Learn

Create a bool query with must, should, and filter clauses

Use exact field names: genre, author, price

Use term queries for exact matches and range query for price

Combine queries correctly inside the bool query

💡 Why This Matters

🌍 Real World

Bool queries are used in search engines to combine multiple search conditions, like filtering products by category, price, and brand.

💼 Career

Understanding bool queries is essential for roles involving search engine development, data retrieval, and Elasticsearch administration.

1

DATA SETUP: Create the base bool query structure

Create a variable called query and set it to a dictionary with a bool key containing empty must, should, and filter lists.

Elasticsearch

query = {
    "bool": {
        "must": [],
        "should": [],
        "filter": []
    }
}
# Your code here

Need a hint?

Think of must, should, and filter as boxes where you put different search rules.

2

CONFIGURATION: Add a must clause for genre

Add a term query inside the must list of query["bool"] to match genre exactly to "fiction".

Elasticsearch

query = {
    "bool": {
        "must": [],
        "should": [],
        "filter": []
    }
}
# Add a term query for genre 'fiction' inside must list

Need a hint?

Use a term query to find exact matches for genre.

3

CORE LOGIC: Add should and filter clauses for author and price

Add a term query for author equal to "John Doe" inside the should list, and add a range query inside the filter list to find books with price less than or equal to 20.

Elasticsearch

query = {
    "bool": {
        "must": [
            {"term": {"genre": "fiction"}}
        ],
        "should": [],
        "filter": []
    }
}
# Add term query for author 'John Doe' inside should list
# Add range query for price <= 20 inside filter list

Need a hint?

Use should for optional matches and filter for conditions that don't affect scoring.

4

OUTPUT: Print the final bool query

Write a print(query) statement to display the complete bool query dictionary.

Elasticsearch

query = {
    "bool": {
        "must": [
            {"term": {"genre": "fiction"}}
        ],
        "should": [
            {"term": {"author": "John Doe"}}
        ],
        "filter": [
            {"range": {"price": {"lte": 20}}}
        ]
    }
}
# Print the query dictionary

Need a hint?

Use print(query) to see the full bool query.