How to create custom category attribute in Magento

>> If you need to create a category attribute there's no option in magento admin. You need to create it through code or sql. I'm showing the two:

1) Here you can use this code with a new module or create a upgrade sql  for an existing module and write below code by changing your attribute code/Label name.

$installer = $this;
$installer->startSetup();

$setup = new Mage_Eav_Model_Entity_Setup('core_setup');

$setup->addAttribute('catalog_category', 'custom_attribute', array(
    'type' => 'int',        // "varchar" for input type text box
    'group'     => 'General Information',
    'backend' => '',
    'frontend' => '',
    'label' => 'Custom Attribute',
    'input' => 'select',    // "text" for input type text box
    'class' => '',
    'source' => 'eav/entity_attribute_source_boolean',            // Leave blank for input type text box
    'global' => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_GLOBAL,
    'visible' => true,
    'required' => false,
    'user_defined' => false,
    'default' => '0',        //Leave blank for input type text box
    'searchable' => false,
    'filterable' => false,
    'comparable' => false,
    'visible_on_front' => false,
    'unique' => false,
));

$installer->endSetup();

                                                                           OR
2)  Or you can run direct sql like this way:

        INSERT INTO `eav_attribute` (`attribute_id`, `entity_type_id`, `attribute_code`, `attribute_model`, `backend_model`, `backend_type`, `backend_table`, `frontend_model`, `frontend_input`, `frontend_label`, `frontend_class`, `source_model`, `is_required`, `is_user_defined`, `default_value`, `is_unique`, `note`) VALUES ('', 3, 'mp3', NULL, '', 'varchar', '', '', 'text', 'Mp3 URL', '', '', 1, 0, '', 0, '');

**** Suppose last inserted ID is 134. This ID will place in the following two table.

        INSERT INTO `eav_entity_attribute` (`entity_attribute_id`, `entity_type_id`, `attribute_set_id`, `attribute_group_id`, `attribute_id`, `sort_order`) VALUES ('', 3, 3, 3, 134, 10);

   Note:- Please check in your database for your attribute type_id , set_id and group_id.

        INSERT INTO `catalog_eav_attribute` (`attribute_id`, `frontend_input_renderer`, `is_global`, `is_visible`, `is_searchable`, `is_filterable`, `is_comparable`, `is_visible_on_front`, `is_html_allowed_on_front`, `is_used_for_price_rules`, `is_filterable_in_search`, `used_in_product_listing`, `used_for_sort_by`, `is_configurable`, `apply_to`, `is_visible_in_advanced_search`, `position`, `is_wysiwyg_enabled`, `is_used_for_promo_rules`) VALUES (134, '', 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, '', 0, 0, 0, 0);


Note* : Will suggest to follow the first step and follow the second to know the table reference.