Bool query in depth in Elasticsearch - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a bool query in Elasticsearch?

A bool query lets you combine multiple queries using logical operators like must, should, must_not, and filter. It helps build complex search conditions.

beginner

Explain the must clause in a bool query.

The must clause means all queries inside it must match the document for it to be included in results. Think of it as an AND condition.

beginner

What does the should clause do in a bool query?

The should clause means at least one of the queries inside should match. It acts like an OR condition and can boost relevance if matched.

intermediate

How does the filter clause differ from must in a bool query?

The filter clause also requires matching documents but does not affect scoring. It is faster because it caches results and is used for filtering without relevance impact.

beginner

What is the role of must_not in a bool query?

must_not excludes documents that match the queries inside it. It works like a NOT condition to remove unwanted results.

Which bool query clause excludes documents from the results?

A should

B must

C must_not

D filter

The must_not clause excludes documents that match its queries.

Which clause in a bool query does NOT affect the relevance score?

A must

B filter

C must_not

D should

The filter clause filters documents without changing their relevance score.

If you want all conditions to be true for a document, which clause do you use?

A must

B should

C filter

D must_not

The must clause requires all its queries to match, like an AND condition.

What happens if a bool query has multiple should clauses but no must or filter clauses?

A At least one should clause must match

B No documents will match

C All should clauses must match

D Should clauses are ignored

When only should clauses exist, at least one should clause must match.

Which clause is best for caching and improving performance in bool queries?

A must_not

B should

C must

D filter

Filter clauses are cached and improve query performance.

Describe the four main clauses of a bool query and their roles.

Think about AND, OR, NOT, and filtering without scoring.

Explain how the filter clause improves query performance compared to must.

Focus on caching and scoring differences.