在同一個表中如何將多個選擇，在單個查詢

Question

我希望有一個單一查詢多個選擇，我的目的是爲了降低MySQL的過程，所以我用這個查詢，但它不工作：

SELECT * 
    FROM `my_setting` 
WHERE `setting` = `site_url` 
    AND `setting` = `site_name` 

我使用select UNION查詢，但我認爲它不會減少內存。

Answer 1

我認爲你想要麼：

SELECT * FROM my_setting 
WHERE `setting` in ('site_url', 'site_name') -- if site_url is a literal string 

或

SELECT * FROM my_setting 
WHERE `setting` in (site_url, site_name) -- if site_url is a column name 

Answer 2

試試這個：你需要去

SELECT * FORM `my_setting` WHERE (`setting` = `site_url` OR `setting` = `site_name`) 

應該讓你。