Check if value already exist by filtering post object

• Yaser2003

• April 6, 2020 at 5:53 am

Hi everyone, I have a post object field and a number field in “post” post type, and i want to check if value already exists in number field in posts that have the same value in post object field,

function validate_field_name_filter($valid, $value, $field, $input) {
  if (!$valid || $value == '') {
    return $valid;
  }
  // query posts for the same value
  // for more info see
  // http://codex.wordpress.org/Class_Reference/WP_Query
  global $post; 
  $arg = array(
	  'post_type' => 'post',
	  'meta_key' => 'chapter_num',
	  'meta_query' => array(
	  	'key' => 'manga_title',
	  	'value' => '"'.get_the_ID().'"',
		'compare' => '!=',
	  ));
  $args = array(
    'post_type' => 'post',  // or your post
    'posts__not_in' => array($arg), // do not check this post
    'meta_query' => array( 
      array(
        'key' => 'chapter_num',
        'value' => $value
      )
    )
  );
  $query = new WP_Query($args);
  if (count($query->posts)) {
    // found at least one post that
    // already has $value
    $valid = 'there is a post have the same number!';
  }
  return $valid;
}

this is my code, but it is not working.
is it possible to do what I want?