Actually, I am posting this because recently I need to get all the meta values of all posts of particular custom post type.
My need was to create a select box dynamically by the only option field which was filled in custom field. So just copy this to your template or header file.
<?php function get_meta_values( $key = '', $type = 'post', $status = 'publish' ) {
global $wpdb;
if( empty( $key ) )
return;
$r = $wpdb->get_col( $wpdb->prepare( "
SELECT pm.meta_value FROM {$wpdb->postmeta} pm
LEFT JOIN {$wpdb->posts} p ON p.ID = pm.post_id
WHERE pm.meta_key = '%s'
AND p.post_status = '%s'
AND p.post_type = '%s'
", $key, $status, $type ) );
return $r;
}
$meta_value = get_meta_values( 'city', 'coach' ); // city & coach are meta_key & post_type respectively.
?>
<select name="city">
<option value="">Select City</option>
<?php foreach ($meta_value as $value) { echo '<option value="'.$value.'">'.$value.'</option>';
}?>
</select>
