WordPress: meta_query with custom fields ( posts get by sub-field ) (WP_QUERY)
Introduction
In the world of WordPress development, working with custom fields and meta queries can be a powerful way to retrieve and display specific content. One common scenario is the need to query posts based on a custom field that has a sub-field or a specific pattern in the meta key. This is where the meta_query
parameter in the WP_Query
class can come in handy.
In this article, we'll explore how to use the meta_query
parameter to retrieve posts based on a custom field that has a sub-field or a specific pattern in the meta key. We'll also look at a real-world example and provide a step-by-step guide on how to implement this functionality in your WordPress projects.
Understanding the meta_query
parameter
The meta_query
parameter in the WP_Query
class allows you to perform complex queries on custom fields (also known as post meta) associated with your WordPress posts. This parameter accepts an array of query clauses, where each clause can specify a meta key, a comparison operator, and a value to match.
Here's a basic example of how to use the meta_query
parameter:
$args = array(
'post_type' => 'post',
'meta_query' => array(
array(
'key' => 'custom_field_name',
'value' => 'custom_field_value',
),
),
);
$query = new WP_Query( $args );
In this example, the meta_query
parameter is used to retrieve posts where the custom_field_name
meta key has the value custom_field_value
.
Querying posts by sub-field or specific pattern
Now, let's take a look at the scenario where you need to retrieve posts based on a custom field that has a sub-field or a specific pattern in the meta key.
Imagine you have a custom post type called cpt_articles
, and each article has a set of custom fields that store additional information. One of these custom fields is called add_info
, and it has several sub-fields, such as add_info_1_ai_comment
, add_info_2_ai_comment
, and so on.
To retrieve the posts where any of the add_info_*_ai_comment
sub-fields are not empty, you can use the following meta_query
structure:
$args = array(
'post_type' => 'cpt_articles',
'meta_query' => array(
'relation' => 'AND',
array(
'key' => 'add_info_%_ai_comment',
'value' => '',
'compare' => '!=',
'type' => 'CHAR',
),
),
);
$query = new WP_Query( $args );
In this example, the meta_query
parameter is used to retrieve posts where any of the add_info_*_ai_comment
sub-fields have a non-empty value. The 'key' => 'add_info_%_ai_comment'
clause uses a wildcard (%
) to match any sub-field that follows the add_info_
pattern. The 'compare' => '!='
clause ensures that posts with a non-empty value are retrieved, and the 'type' => 'CHAR'
clause specifies that the comparison should be done as a string, rather than a numeric value.
Real-world example
Let's take a look at a real-world example that demonstrates how to use the meta_query
parameter to retrieve posts based on a custom field with a sub-field.
Suppose you have a WordPress website that uses a custom post type called cpt_articles
. Each article has a set of custom fields, including add_info_1_ai_comment
, add_info_2_ai_comment
, and so on. You want to retrieve the 10 most recent articles where any of the add_info_*_ai_comment
sub-fields are not empty, and order them by the value of the add_info_*_ai_comment
sub-field that has the highest value.
Here's the code to achieve this:
$args = array(
'post_type' => 'cpt_articles',
'post_status' => array('publish', 'private'),
'meta_query' => array(
'relation' => 'AND',
array(
'key' => 'add_info_%_ai_comment',
'value' => '',
'compare' => '!=',
'type' => 'CHAR',
),
),
'orderby' => 'meta_value',
'order' => 'DESC',
'meta_key' => 'add_info_%_ai_comment',
'posts_per_page' => 10,
);
$query = new WP_Query( $args );
Let's break down the code:
'post_type' => 'cpt_articles'
: This specifies that we want to retrieve posts of the cpt_articles
custom post type.
'post_status' => array('publish', 'private')
: This ensures that we retrieve both published and private articles.
'meta_query' => array()
: This is where we define the meta_query
parameters.
'relation' => 'AND'
: This means that all the clauses in the meta_query
array must be true for a post to be included in the results.
'key' => 'add_info_%_ai_comment'
, 'value' => '', 'compare' => '!='
, 'type' => 'CHAR'
: This clause retrieves posts where any of the add_info_*_ai_comment
sub-fields have a non-empty value.
'orderby' => 'meta_value'
, 'order' => 'DESC'
, 'meta_key' => 'add_info_%_ai_comment'
: These parameters sort the retrieved posts in descending order based on the value of the add_info_*_ai_comment
sub-field with the highest value.
'posts_per_page' => 10
: This limits the number of retrieved posts to the 10 most recent ones.
By using this WP_Query
setup, you can easily retrieve the 10 most recent articles where any of the add_info_*_ai_comment
sub-fields are not empty, and order them by the value of the sub-field with the highest value.
Conclusion
In this article, we've explored how to use the meta_query
parameter in the WP_Query
class to retrieve posts based on a custom field that has a sub-field or a specific pattern in the meta key. We've provided a real-world example and a step-by-step guide on how to implement this functionality in your WordPress projects.
By mastering the use of meta_query
, you can unlock powerful data-driven functionality in your WordPress websites and applications. Whether you need to retrieve posts based on custom field values, sort them based on meta data, or perform complex queries, the meta_query
parameter is a valuable tool in your WordPress development toolkit.
For more information on how Flowpoint.ai can help you identify and fix technical errors that are impacting your website's conversion rates, be sure to check out our website
Get a Free AI Website Audit
Automatically identify UX and content issues affecting your conversion rates with Flowpoint's comprehensive AI-driven website audit.