您可以使用post_parent__not_in 参数：

$args = array( 
           \'post_type\'           => \'cpt\',
           \'post_parent__not_in\' => array( 0 ) 
);
$query = new WP_Query( $args );

然后，生成的SQL将包括以下部分：

wp_posts.post_parent NOT IN (0)

据我所知，你的要求，我想这就是你所需要的。

我已经记录了代码，请检查一下。

<?php
/*
Idea:   Collecting all the posts child posts by --->\'post_parent__not_in\' => array( 0 )<--- 
        in wp_query. Then find their parent posts by eliminating duplicates.
*/

    $query_array = array(
            //Change this post type to your Custom-Post-Type.
        \'post_type\' => \'news\',
            //Showing all posts
        \'posts_per_page\' => -1, 
            //Giving all child posts only
        \'post_parent__not_in\' => array( 0 ) 
        );

    $the_query = new WP_Query($query_array);
        //Array to collect all parent posts
    $collect_parents = array();
    while($the_query->have_posts()):
        $the_query->the_post();
            //if condition is used to eliminate duplicates, generated by same child post of parent.
        if(!in_array($post->post_parent, $collect_parents)){
            //$collect_parents contains all the parent post id\'s
            $collect_parents[] = $post->post_parent;
        }

    endwhile;
        //Printing all the parent posts
    foreach($collect_parents as $parent){
        ?>
        <!-- Printing parent post title -->
        <h2><a href="<?php echo get_permalink($parent ); ?>"> <?php echo get_the_title($parent); ?></a></h2>
        <!-- Printing parent post content -->
        <p><?php echo get_post_field( \'post_content\', $parent); ?></p>
        <?php
    }
?>