仅针对多种类型中的一种折叠和求和组

Question

一开始我有一个table的付款，相关数据是这样的

id     | price  | type     | ts
------ | -------|----------|---------------------------
1      | 50     | Payment  | 2016-06-24 16:01:00.000000
2      | 15     | Payment  | 2016-06-24 16:02:00.000000
3      | 5      | Refund   | 2016-06-24 16:03:00.000000
4      | 10     | Payment  | 2016-06-24 16:04:00.000000
5      | 20     | Payment  | 2016-06-24 16:05:00.000000
6      | 40     | Withdraw | 2016-06-24 16:06:00.000000
7      | 30     | Withdraw | 2016-06-24 16:07:00.000000
8      | 15     | Payment  | 2016-06-24 16:08:00.000000
9      | 25     | Payment  | 2016-06-24 16:09:00.000000

我想要的是将类型为 'Payment' 的所有行折叠成总和、开始和结束期间的形式，所有其他必须相同，所以结果看起来像这样

id     | price  | type     | begin                     | end 
------ | -------|----------|---------------------------|---------------------------
null   | 65     | Payment  | 2016-06-24 16:01:00.000000| 2016-06-24 16:02:00.000000
3      | 5      | Refund   | 2016-06-24 16:03:00.000000|
null   | 30     | Payment  | 2016-06-24 16:04:00.000000| 2016-06-24 16:05:00.000000
6      | 40     | Withdraw | 2016-06-24 16:06:00.000000|
7      | 30     | Withdraw | 2016-06-24 16:07:00.000000|
null   | 40     | Payment  | 2016-06-24 16:08:00.000000| 2016-06-24 16:09:00.000000

如果它有一些标志也会很有用，比如行被分组，并支持限制最终结果

现在我停止尝试 row_number、group by、lag 和其他，找不到正确的方法

UPD：link 到 sql fiddle 工作结果 http://sqlfiddle.com/#!15/3cfea/1/0

Answer 1

这有点棘手。您可以使用行号差异技巧来获取付款组。然后您可以使用 case 仅将其应用于付款本身（而不是其他值）。这看起来像：

select (case when type <> 'payment' then id) as id,
       sum(price) as price,
       min(type) as type,
       min(ts) as begin,
       max(case when type = 'payment' then ts end) as end
from (select t.*,
             (row_number() over (order by id) -
              row_number() over (partition by type order by id)
             ) as grp
      from t
     ) t
group by (case when type = 'payment' then grp end),
         (case when type <> 'payment' then id end);

仅针对多种类型中的一种折叠和求和组

Fold and sum groups only for one of many types

sql

postgresql

postgresql-9.5