mysql - mysql如何让条件或条件优先于其他条件？

Question

我有一个使用子查询的 sql 查询。

SELECT t.id FROM subjects t 
where t.topic_id IN (13,11) 
  AND t.id  not in (select subject_id 
                    from user_visited_subjects uvs
                    where uvs.user_id = 3 )  
  OR t.id in (select subject_id
              from user_subject_suggestions uss 
              where uss.user_id = 3 )  
limit 10

我要给优先级或条件意味着sql应该检查查询中是否有任何记录

OR t.id in (select subject_id from user_subject_suggestions uss where uss.user_id = 3 )

然后检查其他条件。

请指教。

谢谢

Answer 1

只需使用括号。

例子:

SELECT t.id FROM subjects t 
WHERE t.id IN (SELECT subject_id FROM user_subject_suggestions uss WHERE uss.user_id = 3 )
    OR (t.topic_id IN (13,11) 
        AND t.id  NOT IN (SELECT subject_id FROM user_visited_subjects uvs WHERE uvs.user_id = 3 ))
LIMIT 10