Why custom queries retrieve specific data in Wordpress - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a custom query that retrieves posts of type 'product'.

Wordpress

<?php
$args = array('post_type' => '[1]');
$query = new WP_Query($args);
?>

Drag options to blanks, or click blank then click option'

Apage

Bpost

Cproduct

Dattachment

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'post' instead of 'product' will fetch blog posts, not products.

Leaving 'post_type' empty fetches default posts.

The 'post_type' argument specifies which type of posts to retrieve. Using 'product' fetches only product posts.

2fill in blank

medium

Complete the code to retrieve posts ordered by their publish date in descending order.

Wordpress

<?php
$args = array('orderby' => '[1]', 'order' => 'DESC');
$query = new WP_Query($args);
?>

Drag options to blanks, or click blank then click option'

Atitle

Bdate

Cauthor

Dmodified

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'title' orders alphabetically, not by date.

Using 'author' orders by who wrote the post.

Ordering by 'date' sorts posts by their publish date. 'DESC' means newest first.

3fill in blank

hard

Fix the error in the code to retrieve posts with the category ID 5.

Wordpress

<?php
$args = array('cat' => [1]);
$query = new WP_Query($args);
?>

Drag options to blanks, or click blank then click option'

Acategory

B'5'

C"5"

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes makes the ID a string, which causes the query to fail.

Using 'category' instead of the ID is incorrect.

The 'cat' parameter expects an integer ID, so 5 without quotes is correct.

4fill in blank

hard

Fill both blanks to retrieve posts with meta key 'price' greater than 100.

Wordpress

<?php
$args = array(
  'meta_key' => '[1]',
  'meta_value' => 100,
  'meta_compare' => '[2]'
);
$query = new WP_Query($args);
?>

Drag options to blanks, or click blank then click option'

Aprice

B>

C<

Dcost

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' will get values less than 100, which is wrong here.

Using wrong meta key names will return no results.

'meta_key' specifies the custom field name, and 'meta_compare' with '>' filters values greater than 100.

5fill in blank

hard

Fill all three blanks to retrieve published 'event' posts ordered by title ascending.

Wordpress

<?php
$args = array(
  'post_type' => '[1]',
  'post_status' => '[2]',
  'orderby' => '[3]',
  'order' => 'ASC'
);
$query = new WP_Query($args);
?>

Drag options to blanks, or click blank then click option'

Aevent

Bpublish

Ctitle

Ddraft

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'draft' status will not show published posts.

Ordering by anything other than 'title' changes the sort order.

'post_type' set to 'event' fetches event posts, 'post_status' 'publish' gets only published posts, and ordering by 'title' sorts alphabetically.

Practice

1. What is the main reason to use a custom query in WordPress?

easy

A. To retrieve specific posts based on filters like category or author

B. To change the WordPress theme

C. To update the WordPress core automatically

D. To create new user accounts

Solution

1. Step 1: Understand the purpose of custom queries

   Custom queries allow you to select posts based on specific rules like category, author, or date.

2. Step 2: Compare with other options

   Changing themes, updating core, or creating users are unrelated to querying posts.

3. Final Answer:

   To retrieve specific posts based on filters like category or author -> Option A

4. Quick Check:

   Custom queries = filter posts [OK]

Hint: Custom queries filter posts; others change site settings [OK]

Common Mistakes:

• Confusing custom queries with theme changes
• Thinking custom queries update WordPress core
• Assuming custom queries create users

2. Which of the following is the correct way to start a custom query in WordPress?

easy

A. $query = new WP_Query('category_name=news');

B. $query = new WP_Query(['category_name' => 'news']);

C. new WP_Query(['category_name' => 'news']);

D. $query = WP_Query('category=news');

Solution

1. Step 1: Check WP_Query syntax

   WP_Query expects an array of arguments inside new WP_Query([...]).

2. Step 2: Identify correct array syntax

   $query = new WP_Query(['category_name' => 'news']); uses the correct PHP array syntax with key 'category_name' and value 'news'.

3. Final Answer:

   $query = new WP_Query(['category_name' => 'news']); -> Option B

4. Quick Check:

   Correct WP_Query syntax = $query = new WP_Query(['category_name' => 'news']); [OK]

Hint: Use new WP_Query with array args in brackets [OK]

Common Mistakes:

• Passing query as string instead of array
• Missing 'new' keyword before WP_Query
• Using wrong argument keys like 'category'

3. Given this code snippet, what posts will the custom query retrieve?

$args = ['author' => 5, 'posts_per_page' => 3];
$query = new WP_Query($args);
while ($query->have_posts()) {
  $query->the_post();
  echo get_the_title() . '
';
}

medium

A. The latest 3 posts by author with ID 5

B. All posts except those by author 5

C. 3 random posts from any author

D. Posts from author 5 but unlimited number

Solution

1. Step 1: Analyze query arguments

   The 'author' => 5 limits posts to author ID 5, 'posts_per_page' => 3 limits to 3 posts.

2. Step 2: Understand loop output

   The loop prints titles of these 3 posts by author 5.

3. Final Answer:

   The latest 3 posts by author with ID 5 -> Option A

4. Quick Check:

   Author 5 + 3 posts = The latest 3 posts by author with ID 5 [OK]

Hint: Author ID and posts_per_page limit results [OK]

Common Mistakes:

• Ignoring posts_per_page limit
• Confusing author filter as exclusion
• Assuming random posts without filter

4. What is wrong with this custom query code snippet?

$args = ['category_name' => 'news'];
$query = new WP_Query($args);
while ($query->have_posts()) {
  $query->the_post();
  echo get_the_title() . '
';
}

medium

A. The WP_Query object is not created correctly

B. The category_name argument is invalid

C. The loop will never run because have_posts() is missing

D. It does not reset post data after the loop

Solution

1. Step 1: Check query and loop correctness

   The query and loop syntax are correct and will run.

2. Step 2: Identify missing reset

   After a custom query loop, you must call wp_reset_postdata() to restore global post data.

3. Final Answer:

   It does not reset post data after the loop -> Option D

4. Quick Check:

   Missing wp_reset_postdata() = It does not reset post data after the loop [OK]

Hint: Always reset post data after custom query loops [OK]

Common Mistakes:

• Forgetting wp_reset_postdata() after loop
• Thinking category_name is invalid
• Assuming have_posts() is missing

5. You want to retrieve posts from category 'events' published after January 1, 2023, and only those with a custom field 'featured' set to 'yes'. Which WP_Query arguments array will achieve this?

hard

A. {'category_name' => 'events', 'date_query' => [['before' => '2023-01-01']], 'meta_query' => [['key' => 'featured', 'value' => 'yes']] }

B. {'category' => 'events', 'date' => '2023-01-01', 'meta_key' => 'featured', 'meta_value' => 'yes'}

C. {'category_name' => 'events', 'date_query' => [['after' => '2023-01-01']], 'meta_query' => [['key' => 'featured', 'value' => 'yes']]}

D. {'category_name' => 'events', 'date_query' => [['after' => '2023-01-01']], 'meta_key' => 'featured', 'meta_value' => 'no'}

Solution

1. Step 1: Check category and date filters

   'category_name' => 'events' and 'date_query' with 'after' => '2023-01-01' correctly filter posts after that date.

2. Step 2: Verify custom field filter

   'meta_query' with key 'featured' and value 'yes' filters posts with that custom field set.

3. Step 3: Compare options

   {'category_name' => 'events', 'date_query' => [['after' => '2023-01-01']], 'meta_query' => [['key' => 'featured', 'value' => 'yes']]} uses correct keys and nested arrays for date_query and meta_query. Others have wrong keys or values.

4. Final Answer:

   {'category_name' => 'events', 'date_query' => [['after' => '2023-01-01']], 'meta_query' => [['key' => 'featured', 'value' => 'yes']]} -> Option C

5. Quick Check:

   Correct filters + meta_query = {'category_name' => 'events', 'date_query' => [['after' => '2023-01-01']], 'meta_query' => [['key' => 'featured', 'value' => 'yes']]} [OK]

Hint: Use date_query and meta_query arrays for complex filters [OK]

Common Mistakes:

• Using 'category' instead of 'category_name'
• Wrong date_query keys like 'before' instead of 'after'
• Confusing meta_key/meta_value with meta_query array