Change Wordpress Posts' last_modified date and time with WP Query - php

Question

I need to change the last modified date and time of all of my blog's posts in WordPress. So far i have....
add_action( 'wp', 'asd' );
function asd()
{
$post_list = get_posts( array(
'post_per_page' => '-1'
) );
foreach ( $post_list as $post ) {
// $posts[] += $post->ID;
$postID = $post->ID;
$datetime = date( 'Y-m-d H:i:s', current_time( 'timestamp', 0 ) );
echo $postID . ' ||| ' . $datetime . '<br>';
global $wpdb;
$wpdb->query( "UPDATE `$wpdb->posts` SET `post_modified` = '" . $datetime . "' WHERE ID = " . $postID);
}
}
I get no errors or whatsoever. I am using "echo" for debugging purposes. I have two problems.
I have 6 posts and i get only 5
It seems that no update is happening in the database, for the last modified field
Any help would be appreciated.

Answer 1

you use this code.( paste it in your theme function.php)
add_action('init','change_mypost_date');
function change_mypost_date(){
$args = array(
'post_type' => 'property_listing',
'posts_per_page' => -1
);
$the_query = new WP_Query( $args );
if ( $the_query->have_posts() ) {
echo '<ul>';
while ( $the_query->have_posts() ) {
$the_query->the_post();
$datetime = date( 'Y-m-d H:i:s', current_time( 'timestamp', 0 ) );
$current_post = array(
'ID' => get_the_ID(),
'post_modified' => $datetime
);
// Update the post into the database
wp_update_post( $current_post );
}
wp_reset_postdata();
}
}

Answer 2

You are looking to update all of your posts' date to current datetime. So, the solution is without requiring any loops:
add_action( 'init', function () {
$hook = 'run_snippet_daily';
$args = array();
if ( ! wp_next_scheduled( $hook, $args ) ) {
wp_schedule_event( time(), 'daily', $hook, $args );
}
} );
add_action( 'run_snippet_daily', function () {
$datetime = date( 'Y-m-d H:i:s', current_time( 'timestamp', 0 ) );
global $wpdb;
$wpdb->query( "UPDATE `$wpdb->posts`
SET `post_date`='{$datetime}',
`post_modified` ='{$datetime}'
WHERE `post_type`= 'post' ");
} );