Does meta_query need numeric values to be cast to integers?

Question

When pulling numeric data ( a number ) which has been saved to post_meta when editing a page - for example:

$number = get_post_meta( $post->ID, 'number', true ); 

And then using that value with get_posts in a meta_query - for example:

$args = array (
    'posts_per_page'    => 4, // limit ##
    'post_type'         => 'post',
    'post__not_in'      => array ( $post->ID ), // exclude self ##
    'meta_query'        => array (
        array (
            'key'       => 'related_page',
            'value'     => $number,
        )
    ),
);

$posts = get_posts( $args );

Do we first need to type juggle the retrieved value to be an integer, as it appears to be returned as a string:

var_dump($args) gives:

array(5) {
  ["posts_per_page"]=>
  int(4)
  ["post_type"]=>
  string(4) "post"
  ["post__not_in"]=>
  array(1) {
    [0]=>
    int(1387)
  }
  ["meta_query"]=>
  array(3) {
    [0]=>
    array(2) {
      ["key"]=>
      string(15) "related_page"
      ["value"]=>
      string(1) "10"
    }

  }
}

Should I be controlling the values using other custom field settings such as "compare" or "type" ?

Answer 1

The key and value in the postmeta table are technically always strings. even if you were to cast your string to an int it would be cast to a string by the query. Try:

$args = array (
    'post_type'         => 'post',
    'meta_query'        => array (
        array (
            'key'       => 'related_page',
            'value'     => 1,
        )
    ),
);

$posts = new WP_Query( $args );
var_dump($posts->request);

You will notice CAST(wp_postmeta.meta_value AS CHAR) = '1') in that request.

You have to use the type argument to get the query to treat the value as a number. Even with 'type' => 'NUMERIC' you will notice that the value is still treated as a string but cast by the query-- CAST(wp_postmeta.meta_value AS SIGNED) = '1').

And none of this really effects the data returned. Try:

update_post_meta(1,'hal9000',1);
var_dump(get_post_meta(1,'hal9000'));

Put in an integer, get back a string.

PHP is very forgiving about "type" so in many cases it doesn't matter whether you have a string or a int. The big case where it does matter, that I can think of, is sorting. Or, maybe, the case that shows up most on this site. You will need to cast to a integer-- use type if you need the query to sort-- or sorting will be alphabetical and not numeric which do not always align.

Answer 2

The above answer is NOT correct. Here is what you need to do to search between min and max values:

$query_args['meta_query'][] = array(
  'key' => 'your_key_which_is_a_number',
  'value' => array(intval($minimum), intval($maximum)),
  'compare' => 'BETWEEN',
  'type' => 'NUMERIC'
 );

Simply follow this example to make up any other type of search.