基础上多列选择唯一的记录检查

Question

我有一个postgres表fetches下面列

id | status | company_id | created_at 
------------------------------------------- 
10 | success | 2773  | 2017-03-14 
11 | error | 190   | 2017-03-02 
12 | error | 303   | 2017-03-01 
13 | error | 286   | 2017-02-16 
14 | error | 2773  | 2016-12-05 

我想达到以下结果：

id | status | company_id | created_at 
------------------------------------------- 
11 | error | 190   | 2017-03-02 
12 | error | 303   | 2017-03-01 
13 | error | 286   | 2017-02-16 

这是我想的逻辑适用于：

1. 获取所有提取的状态为error。
2. 如果结果包含任何company_id，其最新的fetch（由created_at）为success然后从最终结果集中跳过它。
3. company_id = 2773将被跳过，因为它是最新的获取状态是success

请告知我如何在SQL的方式做到这一点。

Answer 1

尝试外连接：

with succ as (select company_id from fetches where status = 'success') 
select fetches.* 
from fetches 
left outer join succ on succ.company_id = fetches.company_id 
where succ.company_id is null; 

Answer 2

看来你需要一个有状态没有更迭

select * from my_table 
where company_id not in (select company_id from my_table where status = 'success') 

Answer 3

您可以使用窗口功能，这为公司行：

select f.* 
from (select f.*, 
      sum((status = 'success')::int) over (partition by company_id) as isSuccess 
     fetches f 
    ) f 
where isSuccess = 0 and status = 'error';