WordPress $wpdb: Delete all posts of a custom post type with its associated meta data (taxonomies, post meta) using SQL query & $wpdb

delete_custom_post_type.php

<?php
function delete_custom_posts($post_type = 'post'){
    global $wpdb;
    $result = $wpdb->query( 
        $wpdb->prepare("
            DELETE posts,pt,pm
            FROM wp_posts posts
            LEFT JOIN wp_term_relationships pt ON pt.object_id = posts.ID
            LEFT JOIN wp_postmeta pm ON pm.post_id = posts.ID
            WHERE posts.post_type = %s
            ", 
            $post_type
        ) 
    );
    return $result!==false;
}
?>

life saver

Hero. Thank you!