Make a loop to return x number of posts, but only if they have content or excerpt

by

Below is an example — tested and worked.

The SQL query is:

AND ({$wpdb->posts}.post_content != '' OR {$wpdb->posts}.post_excerpt != '')

And the example:

<?php
// This would be in functions.php or somewhere else where appropriate.
function posts_where_require_content_or_excerpt( $where, $wp_query ) {
    global $wpdb;

    $where .= " AND (" .
        " {$wpdb->posts}.post_content != ''" .
        " OR {$wpdb->posts}.post_excerpt != ''" .
    ")";

    return $where;
}


// -- SAMPLE IMPLEMENTATION --

add_filter( 'posts_where', 'posts_where_require_content_or_excerpt', 10, 2 );
query_posts( array(
    'post_type'           => 'post',
    'posts_per_page'      => 5,
    'ignore_sticky_posts' => true,
) );
remove_filter( 'posts_where', 'posts_where_require_content_or_excerpt', 10, 2 );

if ( have_posts() ) {
    echo '<ul>';

        while ( have_posts() ) {
            the_post();

            echo '<li>';

                echo '<h2>'; the_title(); echo '</h2>';
                echo '<p>'; the_excerpt(); echo '</p>';

                printf( '<p><a href="https://wordpress.stackexchange.com/questions/294863/%s">Read More &rarr;</a></p>',
                    esc_url( get_permalink() ) );

            echo '</li>';
        }

    echo '</ul>';

    //the_posts_pagination(); // Needs extra work.
}

wp_reset_query();