How to remove 'GROUP BY' from SQL query produced from get_posts?

Question

Wordpress, Archive Cateory page. From default WP_Query->get_posts() we are getting something like this:

SELECT wp_posts.ID
FROM wp_posts
INNER JOIN wp_term_relationships
ON (wp_posts.ID = wp_term_relationships.object_id)
WHERE 1=1
AND ( wp_term_relationships.term_taxonomy_id IN (5) )
AND wp_posts.post_type = 'post'
AND ((wp_posts.post_status = 'publish'))
GROUP BY wp_posts.ID
ORDER BY wp_posts.post_date DESC
LIMIT 0, 40

I want to remove this: "GROUP BY wp_posts.ID" from this SQL query, is it possible? I've read about pre_get_posts and posts_groupby filter, but I see there is only way to change GROUP BY value, but how to remove it absolutely?

Answer 1

You can use posts_groupby filter:

add_filter( 'posts_groupby', function( $groupby ) {

            return '';

} );

If you want to apply to remove the GROUP BY only to main query and in the frontend, you could do something like this:

add_filter( 'posts_groupby', function( $groupby ) {

    if( ! is_admin() && is_main_query() ) {

            $groupby = '';

    }

    return $groupby;

} );