Postgres ORDER BY使用双精度不正确排序

Question

我正在尝试使用Postgres 9.3.2执行简单的查询。

SELECT event.id AS event_id, event.created_at AS event_created_at, event.updated_at AS  event_updated_at, event.title AS event_title, event.summary AS event_summary, event.image AS event_image, event.active AS event_active, event.raw_score AS event_raw_score, event._score AS event__score, user_1.id AS user_1_id, user_1.email AS user_1_email, user_1.image AS user_1_image, user_1.name AS user_1_name, user_1.password AS user_1_password, user_1.active AS user_1_active, user_1.confirmed_at AS user_1_confirmed_at, user_1.created_at AS user_1_created_at, user_1.updated_at AS user_1_updated_at 
FROM event LEFT OUTER JOIN (users_events AS users_events_1 JOIN "user" AS user_1 ON user_1.id = users_events_1.user_id) ON event.id = users_events_1.event_id ORDER BY event._score DESC

我期待结果按event._score排序，降序，但它们永远不会。它们似乎没有以任何方式与event._score相关联。该列的数据类型是双精度。

我期望值​​的顺序是：

5787.0428202
5787.0427916
5787.0427628

但他们的回复是：

5787.0427916
5787.0427628
5787.0428202

我几十个小时以来一直在努力解决这个问题，并且无法弄清楚为什么这么简单的事情无法正常工作。

Answer 1

经过更多挖掘后，事实证明这不是Postgres的问题，而是我使用的ORM（sqlalchemy）是如何设置的。 _score属性未在数据库中正确设置，尽管它是在会话中设置的，因此会话中的对象返回正确的值，但从数据库中提取的对象不是。