Filtering arguments in GraphQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are filtering arguments in GraphQL?

Filtering arguments are inputs you add to a GraphQL query to get only the data you want. They help narrow down results based on conditions.

beginner

How do you use filtering arguments in a GraphQL query?

You add arguments inside parentheses after the field name. For example: users(age: 25) fetches users who are 25 years old.

beginner

Why are filtering arguments useful?

They reduce the amount of data sent over the network and make queries faster by only returning relevant information.

intermediate

Can filtering arguments be combined in GraphQL?

Yes, you can combine multiple filtering arguments to be more specific. For example: users(age: 25, city: "Paris").

beginner

What happens if you don't use filtering arguments in a GraphQL query?

The query returns all data for that field, which might be a lot and slow down your app or use more data than needed.

How do you specify a filtering argument in a GraphQL query?

A After the closing brace of the query

B Inside curly braces after the field name

C Before the query keyword

D Inside parentheses after the field name

Filtering arguments go inside parentheses right after the field name to narrow down results.

What is the main benefit of using filtering arguments?

A To get all data without limits

B To reduce data and get only what you need

C To change the schema of the API

D To speed up the server hardware

Filtering arguments help get only the data you want, reducing the amount of data transferred.

Can you use multiple filtering arguments together in one query?

A No, only one argument is allowed

B Only if they are the same type

C Yes, you can combine several arguments

D Only if the server is running locally

You can combine multiple filtering arguments to be more specific in your query.

What happens if you omit filtering arguments in a query?

A You get all data for that field

B The server ignores the query

C The query runs faster

D You get an error

Without filtering arguments, the query returns all data for that field.

Which of these is a valid filtering argument example?

A users(age: 30)

B users[age=30]

C users{age: 30}

D users<age=30>

Filtering arguments use parentheses with key-value pairs, like users(age: 30).

Explain what filtering arguments are and why they are useful in GraphQL.

Think about how you ask for only certain items in a list.

Describe how to write a GraphQL query that uses multiple filtering arguments.

Remember the parentheses and commas between arguments.

Practice

1.

What is the main purpose of filtering arguments in a GraphQL query?

easy

A. To get only the data you need by specifying conditions

B. To change the structure of the data returned

C. To add new data to the database

D. To delete data from the database

Solution

1. Step 1: Understand filtering arguments

   Filtering arguments are used to specify conditions that limit the data returned by a query.

2. Step 2: Identify the purpose in the context of data retrieval

   They help get only the data you need, making queries efficient and faster.

3. Final Answer:

   To get only the data you need by specifying conditions -> Option A

4. Quick Check:

   Filtering arguments = get needed data [OK]

Hint: Filtering arguments limit data returned by conditions [OK]

Common Mistakes:

• Thinking filtering changes data structure
• Confusing filtering with data modification
• Assuming filtering adds or deletes data

2.

Which of the following is the correct syntax to filter users by age greater than 25 in a GraphQL query?

{
  users(age_gt: 25) {
    id
    name
  }
}

easy

A. { users(age: {gt: 25}) { id name } }

B. { users(age_gt: 25) { id name } }

C. { users(filter: {age: 25}) { id name } }

D. { users(age > 25) { id name } }

Solution

1. Step 1: Identify correct GraphQL filter syntax

   GraphQL uses argument names like age_gt to filter values greater than 25.

2. Step 2: Compare options with standard syntax

   { users(age_gt: 25) { id name } } uses age_gt: 25 correctly; others use invalid or incorrect syntax.

3. Final Answer:

   { users(age_gt: 25) { id name } } -> Option B

4. Quick Check:

   Correct filter syntax = { users(age_gt: 25) { id name } } [OK]

Hint: Use _gt suffix for 'greater than' filters [OK]

Common Mistakes:

• Using operators like > inside arguments
• Passing filter as nested object incorrectly
• Using equality instead of greater than

3.

Given the query below, what will be the output if the database has users with ages 20, 30, and 40?

{
  users(age_gte: 30) {
    name
  }
}

medium

A. [{"name": "User30"}, {"name": "User40"}]

B. [{"name": "User20"}]

C. [{"name": "User20"}, {"name": "User30"}, {"name": "User40"}]

D. []

Solution

1. Step 1: Understand the filter age_gte: 30

   This filter returns users with age greater than or equal to 30.

2. Step 2: Check which users match the condition

   Users with ages 30 and 40 match; user with age 20 does not.

3. Final Answer:

   [{"name": "User30"}, {"name": "User40"}] -> Option A

4. Quick Check:

   age_gte 30 returns users 30 and 40 [OK]

Hint: gte means greater than or equal [OK]

Common Mistakes:

• Including users younger than 30
• Confusing gte with gt
• Returning empty list incorrectly

4.

Identify the error in the following GraphQL query that tries to filter products by price less than 100:

{
  products(price_lt 100) {
    id
    name
  }
}

medium

A. Incorrect field name 'products' instead of 'productList'

B. Using wrong filter suffix 'lt' instead of 'lessThan'

C. Missing curly braces around filter argument

D. Missing colon ':' between argument name and value

Solution

1. Step 1: Check argument syntax in the query

   The argument price_lt 100 is missing a colon ':' between the argument name and value.

2. Step 2: Confirm correct syntax for filtering

   Correct syntax requires a colon: price_lt: 100.

3. Final Answer:

   Missing colon ':' between argument name and value -> Option D

4. Quick Check:

   Arguments need ':' separator [OK]

Hint: Always use ':' between argument and value [OK]

Common Mistakes:

• Omitting colon ':' after argument name
• Using wrong filter suffix names
• Confusing field names

5.

You want to query a list of books published after 2010 and with more than 300 pages. Which of the following GraphQL queries correctly applies both filters?

{
  books(published_gt: 2010, pages_gt: 300) {
    title
    author
  }
}

hard

A. { books(filter: {published: {gt: 2010}, pages: {gt: 300}}) { title author } }

B. { books(published: {gt: 2010}, pages: {gt: 300}) { title author } }

C. { books(published_gt: 2010, pages_gt: 300) { title author } }

D. { books(published_gt: 2010 pages_gt: 300) { title author } }

Solution

1. Step 1: Understand how to apply multiple filters in GraphQL

   Filters are passed as separate arguments separated by commas.

2. Step 2: Check each option for correct syntax and filter usage

   { books(published_gt: 2010, pages_gt: 300) { title author } } correctly uses commas and proper filter names; others have syntax errors or wrong structure.

3. Final Answer:

   { books(published_gt: 2010, pages_gt: 300) { title author } } -> Option C

4. Quick Check:

   Multiple filters use commas and correct suffixes [OK]

Hint: Separate filters with commas and use _gt suffix [OK]

Common Mistakes:

• Missing commas between arguments
• Using nested filter objects incorrectly
• Omitting colons between argument and value