Question

我在SQL Server 2014数据库中有一个包含200.000行的表，如下所示：

sql = "INSERT INTO outdoorsensorstable (time, col2, col3, col4, col5, col6, col7) "
sql += "VALUES (now(), %s, %s, %s, %s, %s, %s)"
cursor.execute(sql, ('', '', data4, '', data6, ''))

正如您所看到的，每个合约可能存在多个重叠，我希望得到的结果是这样的结果

CREATE TABLE DateRanges
(
     Contract VARCHAR(8),
     Sector VARCHAR(8),
     StartDate DATE,
     EndDate DATE
);

INSERT INTO DateRanges (Contract, Sector, StartDate, Enddate)
   SELECT '111', '999', '01-01-2014', '03-31-2014'
   union
   SELECT '111', '999', '04-01-2014', '06-30-2014'
   union
   SELECT '111', '999', '07-01-2014', '09-30-2014'
   union
   SELECT '111', '999', '10-01-2014', '12-31-2014'
   union
   SELECT '111', '888', '08-01-2014', '08-31-2014'
   union
   SELECT '111', '777', '08-15-2014', '08-31-2014'
   union
   SELECT '222', '999', '01-01-2014', '03-31-2014'
   union
   SELECT '222', '999', '04-01-2014', '06-30-2014'
   union
   SELECT '222', '999', '07-01-2014', '09-30-2014'
   union
   SELECT '222', '999', '10-01-2014', '12-31-2014'
   union
   SELECT '222', '666', '11-01-2014', '11-30-2014'
   UNION
   SELECT '222', '555', '11-15-2014', '11-30-2014';

我无法弄清楚如何做到这一点以及我在这个网站上看到的例子都不适合我的问题。

Answer 1

这个答案使用了一些不同的技巧。第一个是recursive-cte，它会创建一个包含每个相关cal_date的表格，然后使用cross apply来获取具有唯一Contract值的表格，以获取这两个值的每个组合。第二个是window-functions，例如lag和row_number，以确定以下评论中详述的各种内容。最后，也许最重要的是，gaps-and-islands确定一个Contract / Sector组合何时结束，下一个组合结束。

<强>答案：

--determine range of dates 
declare @bgn_dt date = (select min(StartDate) from DateRanges)
    , @end_dt date = (select max(EndDate) from DateRanges)

--use a recursive CTE to create a record for each day / Contract
; with dates as
    (
        select @bgn_dt as cal_date
        union all
        select dateadd(d, 1, a.cal_date) as cal_date
        from dates as a
        where a.cal_date < @end_dt
    )
select d.cal_date
, c.Contract
into #contract_dates
from dates as d
cross apply (select distinct Contract from DateRanges) as c
option (maxrecursion 0)

--Final Select
select f.Contract
, f.Sector
, min(f.cal_date) as StartDate
, max(f.cal_date) as EndDate
from (
    --Use the sum-over to obtain the Island Numbers
    select dr.Contract
    , dr.Sector
    , dr.cal_date
    , sum(dr.IslandBegin) over (partition by dr.Contract order by dr.cal_date asc) as IslandNbr
    from (
        --Determine if the record is the start of a new Island
        select a.Contract
        , a.Sector
        , a.cal_date
        , case when lag(a.Sector, 1, NULL) over (partition by a.Contract order by a.cal_date asc) = a.Sector then 0 else 1 end as IslandBegin
        from (
            --Determine which Contract/Date combinations are valid, and rank the Sectors that are in effect
            select cd.cal_date
            , dr.Contract
            , dr.Sector
            , dr.EndDate
            , row_number() over (partition by dr.Contract, cd.cal_date order by dr.StartDate desc) as ConractSectorRnk
            from #contract_dates as cd
            left join DateRanges as dr on cd.Contract = dr.Contract
                                      and cd.cal_date between dr.StartDate and dr.EndDate
            ) as a
        where a.ConractSectorRnk = 1
        and a.Contract is not null
        ) as dr
    ) as f
group by f.Contract
, f.Sector
, f.IslandNbr
order by f.Contract asc
, min(f.cal_date) asc

<强>输出：

+----------+--------+------------+------------+
| Contract | Sector | StartDate  |  EndDate   |
+----------+--------+------------+------------+
|      111 |    999 | 2014-01-01 | 2014-07-31 |
|      111 |    888 | 2014-08-01 | 2014-08-14 |
|      111 |    777 | 2014-08-15 | 2014-08-31 |
|      111 |    999 | 2014-09-01 | 2014-12-31 |
|      222 |    999 | 2014-01-01 | 2014-10-31 |
|      222 |    666 | 2014-11-01 | 2014-11-14 |
|      222 |    555 | 2014-11-15 | 2014-11-30 |
|      222 |    999 | 2014-12-01 | 2014-12-31 |
+----------+--------+------------+------------+

SQL Server 2014合并重叠日期范围

1 个答案: