我正在尝试修改此function:

// automatically delete users after 7 days in wordpress
function wcs_auto_delete_users() {
global $wpdb;
$query = $wpdb->prepare( "SELECT ID FROM $wpdb->users WHERE datediff( now(), user_registered ) > 7" );
if ( $oldUsers = $wpdb->get_results( $query, ARRAY_N ) ) {
    foreach ( $oldUsers as $user_id ) {
        wp_delete_user( $user_id[0] );
    }
}
}
add_action( \'wcs_daily_clean_database\', \'wcs_auto_delete_users\' );

wp_schedule_event( time(), \'daily\', \'wcs_daily_clean_database\' );

相反，要以不同的方式工作-我希望它自动删除在（比方说）2个月内没有活跃的用户。我有一个插件，可以跟踪用户活动并将数据存储在wp\\u usermeta中。示例：

user_id = 2; meta_key = wp_wp_kc_last_active_time; meta_value = 1422796627

这是我提出的问题：

SELECT user_id FROM wp_usermeta WHERE meta_key = \'wp_wp_kc_last_active_time\' AND TIMESTAMPDIFF( second, now(), TIMESTAMP(SELECT meta_value) ) > 5184000

但它没有选择正确的ID。我应该做什么改变才能让它工作？

SELECT user_id FROM wp_usermeta WHERE meta_key = \'wp_wp_kc_last_active_time\' AND TIMESTAMPDIFF( second, now(), TIMESTAMP(meta_value) ) > 5184000;

SELECT user_id FROM wp_usermeta WHERE meta_key = \'wp_wp_kc_last_active_time\' AND TIMESTAMPDIFF( MONTH, NOW(), FROM_UNIXTIME(meta_value) ) > 2;

global $wpdb;

$query = <<<SQL
 SELECT user_id 
 FROM {$wpdb->usermeta} 
 WHERE 
    meta_key = \'wp_wp_kc_last_active_time\'
    AND DATEDIFF( NOW(), FROM_UNIXTIME( meta_value ) ) > 60
SQL;

$query = $wpdb->prepare( $query );