delete_{$meta_type}_metadata

	 * @since 3.1.0
	 *
	 * @param null|bool $delete     Whether to allow metadata deletion of the given type.
	 * @param int       $object_id  Object ID.
	 * @param string    $meta_key   Meta key.
	 * @param mixed     $meta_value Meta value. Must be serializable if non-scalar.
	 * @param bool      $delete_all Whether to delete the matching metadata entries
	 *                              for all objects, ignoring the specified $object_id.
	 *                              Default false.
	 */
	$check = apply_filters( "delete_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $delete_all );
	if ( null !== $check ) {
		return (bool) $check;
	}

	$_meta_value = $meta_value;
	$meta_value  = maybe_serialize( $meta_value );

	$query = $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s", $meta_key );