Bool query (must, should, must_not, filter) in Elasticsearch - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the must clause do in a Bool query?

The must clause requires that the query conditions inside it must be true for a document to match. Think of it as a strict rule that must be followed.

beginner

Explain the role of the should clause in a Bool query.

The should clause means that if the conditions inside it are true, the document scores higher, but it is not mandatory unless specified. It works like a nice-to-have feature.

beginner

What is the purpose of the must_not clause in a Bool query?

The must_not clause excludes documents that match the conditions inside it. It acts like a filter to remove unwanted results.

intermediate

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

The filter clause also requires conditions to be true, but it does not affect the score of documents. It is used for fast filtering without scoring.

intermediate

Give a simple example of a Bool query using must, should, and must_not.

Example: Find documents where field1 must be 'apple', field2 should be 'red' (optional), and field3 must not be 'rotten'. This means documents must have 'apple', prefer 'red', and exclude 'rotten'.

In a Bool query, which clause excludes documents that match its conditions?

A filter

B must_not

C should

D must

The must_not clause excludes documents matching its conditions.

Which Bool query clause affects scoring of documents?

A filter

B must_not

C must

D none

The must clause affects scoring because it requires matching conditions.

What happens if a document matches a should clause but not a must clause?

A It is excluded

B It always matches

C It never matches

D It matches only if must is empty

Documents must match must clauses; should clauses boost score if must exists.

Which clause is best for fast filtering without scoring?

A filter

B should

C must

D must_not

Filter clause filters documents without affecting score.

If you want to exclude documents with field 'status' equal to 'inactive', which clause do you use?

A must_not

B should

C must

D filter

must_not excludes documents matching the condition.

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

Think about which clauses require, prefer, exclude, or filter documents.

Explain how you would use a Bool query to find documents that must have a value, optionally have another, and exclude a third.

Use must for must-have, should for nice-to-have, must_not for no-go.