How to get data from 2 tables under different conditions?

Question

SQL

Good afternoon.
There are tables:

Setting - list of settings
Setting_Value - list of settings values:

domain_id (null) // Если NULL, то настройка общая, не привязана к домену
   language_id (null) // Если NULL, то настройка общая, не привязана к языку

How do I get a list of all settings for the current domain_id and language_id?
If, for example, some can be with domain_id = null, or with language_id = null (or both columns = null at once)
That is, how not to produce redundant data, and not create copies of the same values ​​for different language_id and domain_id?
Here is an example:
The site_name (Site name) setting can be different for each domain and language
The main_page (main page ID) setting will be the same for all domains, but different for languages
, etc.
The disconnected setting (Does the domain flag is disabled), for all domains except 1 may be the same
How can I not spawn a bunch of redundant data? (although if you make copies for each language, for each domain, there will be no sampling problem)

Answer 1

SELECT *
  FROM setting_salue sv
  JOIN setting s ON s.id = sv.setting_id
  WHERE (sv.domain_id = DOMAIN_ID OR sv.domain_id IS NULL)
    AND (sv.language_id = LANG_ID OR sv.language_id IS NULL)