Filtering arguments in GraphQL - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ query_result

intermediate

Filtering users by age greater than 30

Given the following GraphQL query, what is the expected output if the database contains users with ages 25, 35, and 40?

GraphQL

query {
  users(age_gt: 30) {
    id
    name
    age
  }
}

A [{"id": "1", "name": "John", "age": 25}, {"id": "2", "name": "Alice", "age": 35}, {"id": "3", "name": "Bob", "age": 40}]

B [{"id": "1", "name": "John", "age": 25}]

C [{"id": "2", "name": "Alice", "age": 35}, {"id": "3", "name": "Bob", "age": 40}]

D []

💡 Hint

Think about which users have age greater than 30.

The filter age_gt: 30 returns only users whose age is greater than 30, so users aged 35 and 40 are included.

📝 Syntax

intermediate

Identify the syntax error in filtering by name

Which option contains a syntax error in this GraphQL query filtering users by name?

GraphQL

query {
  users(name_eq: "John") {
    id
    name
  }
}

A query { users(name_eq: John) { id name } }

B query { users(name_eq: "John") { id name } }

C } } eman di { )"nhoJ" :qe_eman(sresu { yreuq

D uery { users(name_eq: "John") { id name } }

💡 Hint

Check if string values are properly quoted.

In GraphQL, string arguments must be enclosed in double quotes. Option A misses quotes around John, causing a syntax error.

❓ optimization

advanced

Optimizing filtering with multiple arguments

Which query is the most efficient to filter users by age greater than 20 and name starting with 'A'?

A query { users(age_gt: 20, name_starts_with: "A") { id name age } }

B query { users { id name age } } # filter client-side

C query { users(age_gt: 20) { id name age } } # then filter name client-side

D query { users(name_starts_with: "A") { id name age } } # then filter age client-side

💡 Hint

Filtering on the server reduces data transfer and processing.

Applying both filters in the query reduces the amount of data sent and processed, making it more efficient.

🧠 Conceptual

advanced

Understanding filtering argument types

Which filtering argument type allows selecting records where a field value is within a list of values?

A contains (substring match)

B gt (greater than)

C eq (equals)

D in (within a list)

💡 Hint

Think about selecting multiple possible values for a field.

The 'in' argument filters records where the field matches any value in a given list.

🔧 Debug

expert

Debugging a filter that returns no results

A query filters users with age_lt: 18 but returns no results, even though the database has users aged 16 and 17. Which option explains the most likely cause?

GraphQL

query {
  users(age_lt: 18) {
    id
    name
    age
  }
}

A The database has no users younger than 18, so no results are returned.

B The filter argument 'age_lt' is not supported by the schema, so it is ignored.

C The query syntax is invalid, causing no results to be returned.

D The filter should be 'age_lt: "18"' with quotes around the number.

💡 Hint

Check if the filtering argument is defined in the schema.

If the schema does not support 'age_lt', the filter is ignored and no filtering happens, possibly returning no results.