从重叠的日期范围中获取不同的连续日期范围

我需要从重叠日期列表中获取彼此不重叠的日期范围列表，并获取重叠期间的硬币总和。我尝试过用谷歌搜索一个例子，但到目前为止还没有运气。我可能没有使用正确的关键词？

我有一个重叠日期的列表

1.1.2018 - 31.1.2018 80
7.1.2018 - 10.1.2018 10
7.1.2018 - 31.1.2018 10
11.1.2018 - 31.1.2018 5
25.1.2018 - 27.1.2018 5
2.2.2018 - 23.2.2018 100

期望的结果是

1.1.2018 - 6.7.2018 80 coins
7.1.2018 - 10.1.2018 100 coins
11.1.2018 - 24.1.2018 95 coins
25.1.2018 - 27.1.2018 100 coins
28.1.2018 - 31.1.2018 95 coins
2.2.2018 - 23.2.2018 100 coins

这是它应该如何工作的图

|------------------------------|
       |---|
       |-----------------------|
           |-------------------|
                      |---|
                                   |----------------------|
Outcome              
|------|---|----------|---|----|   |----------------------|
   80   100     95     100  95                100

这是我的测试数据

drop table coinsonperiod2;
create table coinsonperiod2(
  id serial,
  startdate date,
  enddate date,
  coins integer,
  userid integer
);
insert into coinsonperiod2 (startdate, enddate, coins,userid) values
  ('2018-01-01','2018-01-31', 80,1)
, ('2018-01-07','2018-01-10', 10,1)
, ('2018-01-07','2018-01-31', 10,1)
, ('2018-01-11','2018-01-31', 5,1)
, ('2018-01-25','2018-01-27', 5,1)
, ('2018-02-02','2018-02-23', 100,2)
, ('2018-01-01','2018-01-31', 80,2)
, ('2018-01-07','2018-01-10', 10,2)
, ('2018-01-07','2018-01-31', 10,2)
, ('2018-01-11','2018-01-31', 5,2)
, ('2018-01-25','2018-01-27', 5,2)
, ('2018-02-02','2018-02-23', 100,3)
; 

更新： 事实上斯蒂芬和乔普的回答并没有达到我想要的结果。两个答案都显示结束日期错误。

当一个周期结束时，下一个周期应在第二天开始（如果有间隙，则稍后开始）。在我期望的结果中，2018年1月1日至2018年1月6日包括第6天。第六名和第七名之间没有差距，因为第七名包含在 7.1.2018-10.1.2018 中。

更新2： 现在我明白了开区间、半开区间和闭区间之间的区别。在乔普解决方案中，必须针对半开区间进行计算，但我期望的结果是闭区间。这就是为什么必须减少结束日期以使结果成为闭区间的原因。如果我错了请纠正我。

我还在示例数据中添加了 userid 并进一步修改了 joops 解决方案。 这是给我想要的结果的查询。

with changes AS (
  SELECT
    userid,
    startdate AS tickdate,
    coins,
    1         AS cover
  FROM coinsonperiod2
  UNION ALL
  -- add 1 day to correct intervals into half open intervals, so the calculation is correct
  SELECT
    userid,
    1 + enddate AS tickdate,
    -1 * coins,
    -1          AS cover
  FROM coinsonperiod2
)
, sumchanges  AS (
    SELECT
      userid,
      tickdate,
      SUM(coins) AS change,
      SUM(cover) AS cover
    FROM changes
    GROUP BY tickdate, userid
)
, aggregated AS (
    SELECT
      userid   AS userid,
      tickdate AS startdate,
      lead(tickdate)
      over www AS enddate,
      sum(change)
      OVER www AS cash,
      sum(cover)
      OVER www AS cover
    FROM sumchanges
    WINDOW www AS (
      partition by userid
      ORDER BY tickdate )
)
-- reduce 1 day from the enddate to make closed interval
SELECT
userid
, startdate
, enddate-1 as enddate
, cash
, cover
FROM aggregated
WHERE cover > 0
ORDER BY userid, startdate
;

Outcome:

逻辑是：

• at the 开始间隔的值将其值添加到累积和中
• at the end一个区间的值从这个总和中减去它的值
• 但为了sweep日期线，我们必须收集所有（唯一的）日期/时间戳，无论是开始还是停止。

所以重点是：将一系列数据转换为间隔一系列（开始/停止）events，并对这些进行聚合。

-- \i tmp.sql

create table coinsonperiod(
  id serial,
  startdate date,
  enddate date,
  coins integer
);
insert into coinsonperiod (startdate, enddate, coins) values
  ('2018-01-01','2018-01-31', 80)
, ('2018-01-07','2018-01-10', 10)
, ('2018-01-07','2018-01-31', 10)
, ('2018-01-11','2018-01-31', 5)
, ('2018-01-25','2018-01-27', 5)
, ('2018-02-02','2018-02-23', 100)
        ;

WITH changes AS (
    SELECT startdate AS tickdate , coins
            , 1 AS cover
    FROM coinsonperiod
    UNION ALL
    -- add 1 day to convert to half-open intervals
    SELECT 1+enddate AS tickdate, -1* coins
            , -1 AS cover
    FROM coinsonperiod
    )
, sumchanges  AS (
        SELECT tickdate, SUM(coins) AS change, SUM(cover) AS cover
        FROM changes
        GROUP BY tickdate
        )
, aggregated AS (
        SELECT
        tickdate AS startdate
        , lead(tickdate) over www AS enddate
        , sum(change) OVER www AS cash
          -- number of covered intervals
        , sum(cover) OVER www AS cover
        FROM sumchanges
        WINDOW www AS (ORDER BY tickdate)
        )
             -- substract one day from enddate to correct back to closed intervals
SELECT startdate, enddate-1 AS enddate, cash, cover
FROM aggregated
WHERE cover > 0
ORDER BY startdate
        ;