WP_Query class in Wordpress - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a new WP_Query object.

Wordpress

$query = new [1](['post_type' => 'post']);

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

APost_Query

BQuery_WP

CQueryPost

DWP_Query

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect class names like 'Query_WP' or 'Post_Query'.

Forgetting to use 'new' keyword.

The WP_Query class is used to create custom queries in WordPress. You create a new instance by calling new WP_Query().

2fill in blank

medium

Complete the code to check if the query has posts.

Wordpress

if ($query->[1]()) { echo 'Posts found'; }

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

Ahave_posts

Bposts_exist

Chas_posts

Dfound_posts

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'has_posts()' instead of 'have_posts()'.

Using properties like 'found_posts' instead of methods.

The method have_posts() checks if the query returned any posts.

3fill in blank

hard

Fix the error in the loop to display post titles.

Wordpress

while ($query->[1]()) { $query->the_post(); the_title(); }

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

Ahave_posts

Bnext_post

Cget_post

Dthe_post

Attempts:

3 left

💡 Hint

Common Mistakes

Using the_post() in the while condition (it does not return a boolean).

Using non-existent methods like get_post() or next_post().

The method have_posts() is used in the while condition to iterate over the posts. the_post() sets up the post data inside the loop.

4fill in blank

hard

Fill both blanks to create a query for 5 recent posts of type 'product'.

Wordpress

$args = ['post_type' => [1], 'posts_per_page' => [2]];
$query = new WP_Query($args);

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

A'product'

B5

C'post'

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'post' instead of 'product' for post_type.

Setting posts_per_page to 10 instead of 5.

To query 5 recent 'product' posts, set post_type to 'product' and posts_per_page to 5.

5fill in blank

hard

Fill all three blanks to loop through posts and display their titles with links.

Wordpress

if ($query->[1]()) {
  while ($query->[2]()) {
    $query->the_post();
    echo '<a href="' . get_permalink() . '">' . [3]() . '</a><br>';
  }
}

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

Ahave_posts

Bthe_post

Cthe_title

Dget_posts

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'get_posts()' which returns an array, not a method of WP_Query.

Mixing up 'the_post()' and 'have_posts()' in the loop.

Use have_posts() to check for posts and as the loop condition, the_post() sets up each post inside the loop, and the_title() to display the title.

Practice

1. What is the primary purpose of the WP_Query class in WordPress?

easy

A. To style posts with CSS classes

B. To create new posts in the WordPress admin

C. To fetch posts from the database based on custom criteria

D. To manage user roles and permissions

Solution

1. Step 1: Understand WP_Query's role

   WP_Query is designed to retrieve posts from the database using filters like category, author, or date.

2. Step 2: Differentiate from other WordPress features

   Creating posts, styling, or managing users are handled by other parts of WordPress, not WP_Query.

3. Final Answer:

   To fetch posts from the database based on custom criteria -> Option C

4. Quick Check:

   WP_Query fetches posts = A [OK]

Hint: WP_Query is for getting posts, not creating or styling [OK]

Common Mistakes:

• Confusing WP_Query with post creation functions
• Thinking WP_Query styles posts
• Assuming WP_Query manages users

2. Which of the following is the correct way to start a new WP_Query to get posts from category ID 5?

easy

A. $query = WP_Query(array('cat' => 5));

B. $query = new WP_Query(array('cat' => 5));

C. $query = new WP_Query('category_id' => 5);

D. $query = WP_Query('category' => 5);

Solution

1. Step 1: Check WP_Query instantiation syntax

   WP_Query must be created with the new keyword and an array of arguments.

2. Step 2: Verify correct argument key for category

   The correct key for category ID is 'cat', not 'category' or 'category_id'.

3. Final Answer:

   $query = new WP_Query(array('cat' => 5)); -> Option B

4. Quick Check:

   Use new WP_Query with array('cat' => 5) = D [OK]

Hint: Use new WP_Query with array and 'cat' key for category ID [OK]

Common Mistakes:

• Omitting the new keyword
• Using wrong argument keys like 'category' or 'category_id'
• Passing arguments without array

3. Given the following code, what will be the output if there are 3 posts in category 10?

$query = new WP_Query(['cat' => 10]);
if ($query->have_posts()) {
  while ($query->have_posts()) {
    $query->the_post();
    echo get_the_title() . ', ';
  }
} else {
  echo 'No posts found';
}
wp_reset_postdata();

medium

A. Titles of the 3 posts separated by commas

B. No posts found

C. Syntax error due to missing semicolons

D. Only the first post title printed

Solution

1. Step 1: Understand the loop behavior

   The loop runs while have_posts() returns true, printing each post title followed by a comma.

2. Step 2: Check the number of posts in category 10

   Since there are 3 posts, all 3 titles will be printed separated by commas.

3. Final Answer:

   Titles of the 3 posts separated by commas -> Option A

4. Quick Check:

   Loop prints all post titles = C [OK]

Hint: Loop prints all posts if have_posts() is true [OK]

Common Mistakes:

• Thinking only one post prints
• Assuming 'No posts found' when posts exist
• Confusing syntax errors with correct code

4. What is wrong with this WP_Query usage?

$query = new WP_Query(['post_type' => 'product']);
while ($query->have_posts()) {
  the_post();
  echo get_the_title();
}
wp_reset_postdata();

medium

A. Incorrect post_type value

B. Using echo instead of print

C. Missing wp_reset_query() after the loop

D. Missing call to $query->the_post() inside the loop

Solution

1. Step 1: Check loop method calls

   The loop uses $query->have_posts() but calls the_post() without the query object, which is incorrect.

2. Step 2: Identify correct method usage

   Inside the loop, it should call $query->the_post() to set up post data properly.

3. Final Answer:

   Missing call to $query->the_post() inside the loop -> Option D

4. Quick Check:

   Use $query->the_post() in custom loops = B [OK]

Hint: Use $query->the_post() inside loop, not just the_post() [OK]

Common Mistakes:

• Calling the_post() without query object in custom loops
• Confusing wp_reset_postdata() with wp_reset_query()
• Assuming echo vs print matters here

5. You want to display the latest 5 posts from category 3 but exclude posts tagged with 'featured'. Which WP_Query argument array correctly achieves this?

hard

A. ['cat' => 3, 'posts_per_page' => 5, 'tag__not_in' => [get_term_by('slug', 'featured', 'post_tag')->term_id]]

B. ['category_name' => '3', 'posts_per_page' => 5, 'tag__not_in' => ['featured']]

C. ['cat' => 3, 'posts_per_page' => 5, 'tag__not_in' => ['featured']]

D. ['cat' => 3, 'posts_per_page' => 5, 'tag__not_in' => get_term_by('slug', 'featured', 'post_tag')->term_id]

Solution

1. Step 1: Identify correct category argument

   Use 'cat' => 3 to filter by category ID 3, not 'category_name' with a number string.

2. Step 2: Exclude posts by tag ID

   The tag__not_in argument expects an array of tag IDs, so we must get the ID using get_term_by().

3. Step 3: Check syntax for excluding 'featured' tag

   Using get_term_by('slug', 'featured', 'post_tag')->term_id inside the array correctly fetches the tag ID to exclude.

4. Final Answer:

   ['cat' => 3, 'posts_per_page' => 5, 'tag__not_in' => [get_term_by('slug', 'featured', 'post_tag')->term_id]] -> Option A

5. Quick Check:

   Use tag IDs with tag__not_in, not slugs = A [OK]

Hint: Exclude tags by ID array with tag__not_in, not by slug string [OK]

Common Mistakes:

• Using tag slugs instead of tag IDs in tag__not_in
• Using category_name with numeric ID
• Not wrapping tag IDs in an array