小编Oli*_*son的帖子

条件子查询

我有以下查询:

SELECT id,
   email,
   first_name as "firstName",
   last_name as "lastName",
   is_active as "isActive",
   password,
   access,
   CASE
     WHEN access < 3 THEN (
       SELECT
         CASE WHEN count(*) = 1 THEN true ELSE false END
       FROM user_rating_entity ure
       WHERE ure.user_id = u.id
         AND ure.rating_entity_id = :re_id
     )
     ELSE true
   END as "isResponsible"
FROM users u
WHERE u.id = :id
Run Code Online (Sandbox Code Playgroud)

如果access > 3,字段“isResponsible”应直接设置为true,并且不应执行子查询。我在这两种情况下都使用了解释分析,其中 access>=<to 3但我得到了相同的输出。

为什么呢?

postgresql optimization execution-plan subquery explain

3
推荐指数
2
解决办法
1万
查看次数