SQL Server 中按连续日期分组

Question

我有包含以下列的表格：

[name_of_pos] varchar,
[date_from] datetime,
[date_to] datetime

以下是我的样本数据：

name_of_pos  date_from                 date_to
----------------------------------------------------------------
Asystent     2015-08-26 08:57:49.000   2015-09-04 08:57:49.000
Biuro        2015-09-01 08:53:32.000   2015-09-01 08:53:32.000
Biuro        2015-09-02 09:00:41.000   2015-09-02 09:00:41.000
Biuro        2015-09-03 11:46:03.000   2015-09-03 11:46:03.000
Biuro        2015-09-10 09:02:11.000   2015-09-15 09:02:11.000
Koordynator  2015-09-01 09:04:06.000   2015-09-01 09:04:06.000
Projektant   2015-08-31 08:59:46.000   2015-09-01 08:59:46.000
Projektant   2015-09-02 08:00:54.000   2015-09-02 08:00:54.000
Projektant   2015-09-14 12:34:50.000   2015-09-14 12:34:50.000

我想要返回的是每个的日期范围（最小值date_from到最大值） ，但仅限于日期值连续的情况（时间部分并不重要，可以在结果中忽略）。date_toname_of_pos

期望的输出是：

  name_of_pos   date_from   date_to
  ------------------------------------
  Asystent      2015-08-26  2015-09-04 
  Biuro         2015-09-01  2015-09-03 
  Biuro         2015-09-10  2015-09-15 
  Koordynator   2015-09-01  2015-09-01 
  Projektant    2015-08-31  2015-09-02 
  Projektant    2015-09-14  2015-09-14 

我尝试使用类似于此问题的解决方案：

如何对连续范围进行分组

但没有运气，因为我有两个日期时间列。

Answer 1

这是一个使用 acte迭代行（在排序后）并在分组之前检查连续天数的解决方案：

-- dummy table
CREATE TABLE #TableA
    (
      [name_of_pos] VARCHAR(11) ,
      [date_from] DATETIME ,
      [date_to] DATETIME
    );

-- insert dummy data
INSERT  INTO #TableA
        ( [name_of_pos], [date_from], [date_to] )
VALUES  ( 'Asystent', '2015-08-26 08:57:49', '2015-09-04 08:57:49' ),
        ( 'Biuro', '2015-09-01 08:53:32', '2015-09-01 08:53:32' ),
        ( 'Biuro', '2015-09-02 09:00:41', '2015-09-02 09:00:41' ),
        ( 'Biuro', '2015-09-03 11:46:03', '2015-09-03 11:46:03' ),
        ( 'Biuro', '2015-09-10 09:02:11', '2015-09-15 09:02:11' ),
        ( 'Koordynator', '2015-09-01 09:04:06', '2015-09-01 09:04:06' ),
        ( 'Projektant', '2015-08-31 08:59:46', '2015-09-01 08:59:46' ),
        ( 'Projektant', '2015-09-02 08:00:54', '2015-09-02 08:00:54' ),
        ( 'Projektant', '2015-09-14 12:34:50', '2015-09-14 12:34:50' );

-- new temp table used to add row numbers for data order
SELECT  name_of_pos, CAST(date_from AS DATE) date_from, CAST(date_to AS DATE) date_to,
        ROW_NUMBER() OVER ( ORDER BY name_of_pos, date_from ) rn
INTO    #temp
FROM    #TableA

-- GroupingColumn in cte used to identify and group consecutive dates
;WITH    cte
          AS ( SELECT   name_of_pos ,
                        date_from ,
                        date_to ,
                        1 AS GroupingColumn ,
                        rn
               FROM     #temp
               WHERE    rn = 1
               UNION ALL
               SELECT   t2.name_of_pos ,
                        t2.date_from ,
                        t2.date_to ,
                        CASE WHEN t2.date_from = DATEADD(day, 1, cte.date_to) 
                                  AND cte.name_of_pos = t2.name_of_pos
                             THEN cte.GroupingColumn
                             ELSE cte.GroupingColumn + 1
                        END AS GroupingColumn ,
                        t2.rn
               FROM     #temp t2
                        INNER JOIN cte ON t2.rn = cte.rn + 1
             )
    SELECT  name_of_pos, MIN(date_from) AS date_from, MAX(date_to) AS date_to
    FROM    cte
    GROUP BY name_of_pos, GroupingColumn

DROP TABLE #temp
DROP TABLE #TableA

产生您想要的输出：

name_of_pos date_from   date_to
Asystent    2015-08-26  2015-09-04
Biuro       2015-09-01  2015-09-03
Biuro       2015-09-10  2015-09-15
Koordynator 2015-09-01  2015-09-01
Projektant  2015-08-31  2015-09-02
Projektant  2015-09-14  2015-09-14