Query arguments in GraphQL - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ query_result

intermediate

What is the output of this GraphQL query with arguments?

Given the schema with a books query that accepts an argument author to filter books by author name, what will be the result of this query?

GraphQL

query {
  books(author: "Alice") {
    title
    author
  }
}

A [{"title": "GraphQL Basics", "author": "Bob"}]

B [{"title": "GraphQL Basics", "author": "Alice"}, {"title": "Advanced GraphQL", "author": "Alice"}]

C []

D Error: Unknown argument 'author'

💡 Hint

Think about how the argument filters the list of books by author.

The query filters books where the author is 'Alice', so only books by Alice are returned.

📝 Syntax

intermediate

Which query syntax correctly uses arguments in GraphQL?

Select the query that correctly passes an argument to the user field to fetch a user by ID.

A query { user(id = 5) { name email } }

B query { user { id: 5, name, email } }

C query { user(id: 5) { name email } }

D query { user(id => 5) { name email } }

💡 Hint

Arguments in GraphQL use parentheses and colon syntax.

Option C uses correct syntax: parentheses around arguments and colon to assign values.

❓ optimization

advanced

How to optimize a GraphQL query with multiple arguments to reduce data transfer?

You want to fetch a list of products filtered by category and price range. Which query best reduces unnecessary data transfer?

A query { products(category: "Books", minPrice: 10, maxPrice: 50) { id name price } }

B query { products { id name price category } }

C query { products(category: "Books") { id name price } }

D query { products(minPrice: 10, maxPrice: 50) { id name price } }

💡 Hint

Filtering on the server reduces the amount of data sent.

Option A filters by category and price range, so only matching products are returned, minimizing data.

🔧 Debug

advanced

Why does this GraphQL query with arguments fail?

Given the query below, why does it produce an error?

GraphQL

query {
  user(id: "abc") {
    name
    email
  }
}

A The argument 'id' expects an integer, but a string was provided.

B The query is missing required fields inside 'user'.

C The field 'user' does not accept any arguments.

D The argument 'id' must be passed as a variable, not inline.

💡 Hint

Check the expected type of the argument 'id' in the schema.

If 'id' is defined as an integer, passing a string causes a type error.

🧠 Conceptual

expert

What is the purpose of default argument values in GraphQL queries?

Why would you define default values for arguments in a GraphQL schema?

A To restrict access to certain fields based on argument values.

B To force clients to always provide argument values.

C To improve query execution speed by caching results.

D To allow queries to omit arguments and still get predictable results.

💡 Hint

Think about what happens when a client does not provide an argument.

Default argument values let the server use a fallback value when the client omits the argument, ensuring consistent behavior.