MYSQL查询无法删除文件本身。您必须使用wp\\u delete\\u attachment（）。以下是一个概念证明，您可以根据自己的意愿进行更改。特色图像在Posteta中存储为_thumbnail_id. wp_delete_attachment() 其余的都是为你做的。

<?php
/*
Plugin Name: Delete All Featured Images
Description: Delete all featured images by visiting /?delete-featured-images=1
Version: 0.1
Author: Brian Fegter
Author URI: http://coderrr.com
License: GPL3v2
*/

# USAGE: visit http://yourdomain.com/?delete-featured-images=1

add_action(\'init\', \'foo_bar_delete_featured\', 0);
function foo_bar_delete_featured(){

    # Check for logged in state
    if(!is_user_logged_in())
        return;

    # Check for admin role
    if(!current_user_can(\'manage_options\'))
        return;

    # Check for query string
    if(isset($_GET[\'delete-featured-images\']) && $_GET[\'delete-featured-images\'] == 1){
        global $wpdb;

        # Run a DQL to get all featured image rows
        $attachments = $wpdb->get_results("SELECT * FROM $wpdb->postmeta WHERE meta_key = \'_thumbnail_id\'");

        foreach($attachments as $attachment){

            # Run a DML to remove this featured image row
            $wpdb->query("DELETE FROM $wpdb->postmeta WHERE meta_id = \'$attachment->meta_id\' LIMIT 1");

            # Delete attachment DB rows and files
            wp_delete_attachment($attachment->meta_value, true);

            # Print to screen
            show_message(\'Attachment #$attachment->meta_value deleted.\');
        }
        exit;
    }
}