custom post type search by reference id

You can try using the post_parent paramter or WP_Query ex:

new WP_Query(array(
    'post_type' => 'tab_content',
    'post_parent' => 80
));

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)