aizatto

WP Ajax Query allows you to query your WordPress database using the same query paramaters you would use for WP_Query, and return a JSON respresentation of the query results. This allows developers to easily interface with WordPress without having to relearn a new API.
<h3>How It Works</h3>
The Ajax Query interface would be available at http://example.com/wp-admin/admin-ajax.php?action=query
A sample jQuery request would be like: 
 $.get(ajaxurl, { action: ‘query’ }, function () { }, ‘json’);
Querying for a post: 
 $.get(ajaxurl, { action: ‘query’, p: 1 }, function () { }, ‘json’);
JSON results: 
 { 
 “id”: 1, 
 “type”: ‘post’, 
 “title”: “Hello World”, 
 “permalink”: “http:\/\/example.com\/?p=1” 
 }
Query a category: 
 $.get(ajaxurl, { action: ‘query’, cat: 1 }, function () { }, ‘json’);
JSON results: 
 { 
 “id”: 1 
 “type”: “category”, 
 “permalink”: “http:\/\/example.com\/?cat=1”, 
 “terms”: [], 
 “posts”: [] 
 }
<pre><code>terms and `posts` represents an array of either terms that are sub categories of the category, or posts belonging to the category.<h3>Why I Created It</h3>
</code></pre>
Needed a common way to query the database for posts and taxonomies across multiple plugins, and didn’t find a suitable replacement.

WP Ajax Query

WP Ajax Query allows you to query your WordPress database using the same query paramaters you would use for WP_Query, and return a JSON respresentatio …

Tom Auger

This plugin, once activated, spits out the information passed by each filter used in manipulating database queries, as a learning tool.
The code itself is heavily documented and demonstrates best practices for working with those filters and actions to view / manipulate the query.
It is very important to note that this plugin is not meant for a production environment as it will insert a lot of really ugly HTML throughout your page. You’ll get the most use out of this plugin by looking at its code, and maybe previewing one or two pages on a sandbox, vanilla WordPress site.

Valz Display Query Filters

This demonstration plugin identifies the primary filters that are used by WordPress as it parses your queries.

WP Ajax Query vs Valz Display Query Filters