WordPress plugin - Combine Query
This experimental plugin allows you to combine multiple WP_Query queries into a single one, using the combined_query attribute.
This started as an answer on Stackoverflow, see here and here.
The idea behind this plugin is to combine the SQL queries for each WP_Query() query with UNION or UNION ALL.
I first noticed this technique in a great answer on WordPress Development by Mike Schinkel.
I use the trick mentioned here to preserve the order of UNION sub queries.
This implementation supports combining N sub-queries.
This version is a total rewrite of the plugin.
The WP_Combine_Query class has been removed in favour of simply using the combined_query attribute of the WP_Query class.
Now the plugin only supports PHP versions 5.4+.
The supported settings for the combined_query attribute:
'combined_query' => [
'args' => [ $args1, $args2, ... ], // Array (default [])
'union' => 'UNION', // String Possible values are UNION or UNION ALL (default UNION)
'posts_per_page' => 10, // Integer 1,2,...
'offset' => 0, // Integer 0,1,...
'orderby' => 'meta_value_num', // String (post_name, ..., name, ..., none, meta_value, meta_value_num )
'order' => 'DESC', // String (ASC,DESC)
]
If you want to remove duplicated posts use UNION, else use UNION ALL.
There are two custom filters currently available:
// Modify combined ordering:
add_filter( 'cq_orderby', function( $orderby ) {
return $orderby;
});
// Modify sub fields:
add_filter( 'cq_sub_fields', function( $fields ) {
return $fields;
});
To keep the order by arguments arg1, arg2, ... use:
'combined_query' => [
...
'orderby' => 'none',
...
]
or
add_filter( 'cq_orderby', '__return_empty_string' );
$query = new WP_Query( $args );
remove_filter( 'cq_orderby', '__return_empty_string' );
Upload the plugin to the plugin folder and activate it.
To install dependencies with Composer (not required):
composer install
or
php composer.phar install
within our folder. See here for more information on how to install Composer.
Then play with the examples below, in your theme or in a plugin.
Have fun ;-)
Here we want to display the first published page in an alphabetical order and then the three oldest published posts:
//-----------------
// Sub query #1:
//-----------------
$args1 = [
'post_type' => 'page',
'posts_per_page' => 1,
'orderby' => 'title',
'order' => 'asc',
];
//-----------------
// Sub query #2:
//-----------------
$args2 = [
'post_type' => 'post',
'posts_per_page' => 3,
'orderby' => 'date',
'order' => 'asc',
];
//---------------------------
// Combined queries #1 + #2:
//---------------------------
$args = [
'combined_query' => [
'args' => [ $args1, $args2 ],
'union' => 'UNION',
'posts_per_page' => 4,
'orderby' => 'none',
]
];
//---------
// Output:
//---------
$q = new WP_Query( $args );
if( $q->have_posts() ):
?><ul><?php
while( $q->have_posts() ): $q->the_post();
?><li><a href="<?php the_permalink();?>"><?php the_title();?></a></li><?php
endwhile;
?></ul><?php
wp_reset_postdata();
else:
_e( 'Sorry no posts found!' );
endif;
Here we want to display all foo posts with a date query, sorted by comment count and after that all bar posts sorted by comment count. Then we sort all by decreasing comment count.
//-----------------
// Sub query #1:
//-----------------
$args1 = [
'post_type' => 'foo',
'orderby' => 'comment_count',
'order' => 'desc',
'posts_per_page' => 100, // adjust to your needs
'date_query' => [
[
'after' => date('Y-m-d'),
],
'inclusive' => true,
]
];
//-----------------
// Sub query #2:
//-----------------
$args2 = [
'post_type' => 'bar',
'orderby' => 'comment_count',
'order' => 'desc',
'posts_per_page' => 100, // adjust to your needs
];
//---------------------------
// Combined queries #1 + #2:
//---------------------------
$args = [
'combined_query' => [
'args' => [ $args1, $args2 ],
'posts_per_page' => 5,
'paged' => 2,
'orderby' => 'comment_count',
'order' => 'desc',
]
];
//---------
// Output:
//---------
// See example 1
Let's combine two meta queries and order by a common meta value:
//-----------------
// Sub query #1:
//-----------------
$args1 = [
'post_type' => 'cars',
'posts_per_page' => 10,
'orderby' => 'title',
'order' => 'asc',
'meta_query' => [
[
'key' => 'doors',
'value' => 0,
'compare' => '>=',
'type' => 'UNSIGNED'
],
],
];
//-----------------
// Sub query #2:
//-----------------
$args2 = [
'post_type' => 'post',
'posts_per_page' => 10,
'orderby' => 'date',
'order' => 'desc',
'tax_query' => [
[
'taxonomy' => 'category',
'field' => 'slug',
'terms' => 'cars',
],
],
'meta_query' => [
[
'key' => 'doors',
'value' => 0,
'compare' => '>=',
'type' => 'UNSIGNED'
],
],
];
//------------------------------
// Order by a common meta value
//------------------------------
// Modify sub fields:
add_filter( 'cq_sub_fields', $callback = function( $fields ) {
return $fields . ', meta_value';
});
//---------------------------
// Combined queries #1 + #2:
//---------------------------
$args = [
'combined_query' => [
'args' => [ $args1, $args2 ],
'posts_per_page' => 5,
'orderby' => 'meta_value_num',
'order' => 'DESC',
]
];
//---------
// Output:
//---------
// See example 1
remove_filter( 'cq_sub_fields', $callback );
We could also combine more than two sub queries, here's an example of four sub-queries:
$args = [
'combined_query' => [
'args' => [ $args1, $args2, $args3, $args4 ],
...
]
];
//---------
// Output:
//---------
// See example 1
The above examples are all for secondary queries. So let's add a query to the main home query:
add_action( 'pre_get_posts', function( \WP_Query $q ) {
if( $q->is_home() && $q->is_main_query() ) {
//-----------------
// Sub query #1:
//-----------------
$args1 = [
'post_type' => 'page',
'posts_per_page' => 1,
'orderby' => 'title',
'order' => 'asc',
];
//-----------------
// Original query #2:
//-----------------
$args2 = $q->query;
//---------------------------
// Combined queries #1 + #2:
//---------------------------
$args = [
'combined_query' => [
'args' => [ $args1, $args2 ],
'union' => 'UNION',
'posts_per_page' => 4,
'orderby' => 'none',
]
];
//-----------------------
// Modify the Main query:
//-----------------------
$q->set( 'combined_query', $args['combined_query'] );
}
} );
(2022-03-03)
- Fixed: Wrong plugin URI in header (Props: therealgilles)
1.2.2 (2021-02-20)
- Fixed: Fixes #14 regarding subsequent queries. (Props: @Suranex)
1.2.1 (2020-09-14)
- Fixed: Readme.
1.2.0 (2020-09-14)
- Added: Support for ordering by 'none'.
- Added: Test cases.
- Added: Support for adding parameters (posts_per_page, offset, orderby, order) inside combined_query args.
- Fixed: Hooks handling for pre_get_posts example.
- Adjusted: Examples.
1.1.1 (2020-09-04)
- Added: Example how to keep the order by arguments arg1, arg2, ...
- Adjusted: UNION ALL test
1.1.0 (2020-09-04)
- Added: Ticket #19 - Add test cases for argument order workaround. (Props: therealgilles)
- Cleanup: phpcs
1.0.5 (2016-05-08)
- Fixed: Ticket #8 - Fallback for those who don't use Composer.
- Improved: Removed an explicit call to $GLOBALS['wpdb'] through the use keyword.
- Improved: Simplified the namespace to only CombinedQuery.
1.0.4 (2016-04-21)
- Fixed: Adjusted the paged bug that sneaked in with verion 1.0.2 yesterday.
- Improved: Simplified the example that uses get_query_var() that can now handle default as an input parameter.
1.0.3 (2016-04-21)
- Fixed: Ticket #7 - Not able to set the "UNION ALL" union option
- Improved: Inline docs
1.0.2 (2016-04-20)
- Fixed: Ticket #6 - Escape % in the Generator class. (Props: @DArcMattr)
- Improved: Inline docs
1.0.1 (2015-11-09)
- Fixed: Remove vendor dependency and let the user install it via 'composer install' (Props: @pdufour)
- Fixed: Ignore sticky posts in the EmptyQuery class
1.0.0 (2015-05-10)
- ** Total Plugin Rewrite **
- Closed: Ticket #3
- Added: New classes Main, EmptyQuery and Generator.
- Added: Support for 'combined_query' attribute of the WP_Query class.
- Added: Support only for PHP 5.4+
- Added: Autoload via Composer.
- Added: New filter 'cq_sub_fields' instead of 'cq_sub_fields'
- Added: New filter 'cq_orderby' instead of 'cq_orderby'
0.1.3 (2015-05-09)
- Added: Support for ignory_sticky_posts.
- Fixed: Minor
0.1.2 (2015-05-08)
- Added: Support for the GitHub Updater.
- Added: New filter 'wcq_sub_fields'
- Added: New filter 'wcq_orderby'
- Added: New example for meta value ordering
- Fixed: Ordering didn't work correctly.
0.1.1
- Changed: Coding style and autoloading (Props: @egill)
0.1 Various plugin improvements, for example:
- Added: orderby in the combined query.
- Added: posts_per_page in the sub queries.
- Added: offset in the sub queries.
- Added: paged in the sub queries.
- Removed: sublimit in the combined query, use posts_per_page instead in sub queries.
- Fixed: Issue #1 related to max_num_pages (Props: @hellofantastic).
0.0.4
- Added: support for offset in the combined query
0.0.3
- Added: GPL2+ License part
- Removed: Dropped namespace + anonymous function for wider PHP support.
0.0.2
- Added: Input parameter 'union' with possible values UNION and UNION ALL.
- Fixed: Empty paged resulted in a sql error. (Props: Robert Hue)