連続した日付データをグループ化する SQL Server クエリ

最初のいくつかのテスト データ:

create table seasons (seasonId int primary key
    , "date" datetime not null unique
    , tariffId int not null)

insert into seasons values (1, '2009-01-01', 1)
insert into seasons values (2, '2009-01-02', 1)
insert into seasons values (3, '2009-01-03', 2)
insert into seasons values (4, '2009-01-04', 3)
insert into seasons values (5, '2009-01-05', 3)
insert into seasons values (6, '2009-01-06', 1)
insert into seasons values (7, '2009-01-07', 1)
insert into seasons values (8, '2009-01-08', 3)
-- add a tarrif with a datespan larger than 2
insert into seasons values (9, '2009-01-09', 4)
insert into seasons values (10, '2009-01-10', 4)
insert into seasons values (11, '2009-01-11', 4)

Dave Barker の回答に基づいて、インライン ビュー内に row_number() を追加して、tariId によって最初の最小値、2 番目の最小値などがわかるようにします。 (実際には、1 つの日付に複数のタリフ ID を指定できないため、タリフ ID で分割する必要はありません。)

SELECT MinValues.Seasonid, MinValues.Date, MaxValues.Date, MaxValues.tariffid 
FROM (
    SELECT *, row_number() over (partition by tariffId order by "date") as RN 
      FROM [dbo].[Seasons] tbl1
     WHERE NOT EXISTS (SELECT * 
                         FROM [dbo].[Seasons] tbl2 
                        WHERE tbl1.seasonid - tbl2.seasonid = 1 
                          AND tbl1.tariffId = tbl2.tariffId)) as minValues
JOIN (
     SELECT *, row_number() over (partition by tariffId order by "date") as RN
       FROM [dbo].[Seasons] tbl1
      WHERE NOT EXISTS (SELECT *
                          FROM [dbo].[Seasons] tbl2 
                         WHERE tbl2.seasonid - tbl1.seasonid = 1 
                           AND tbl1.tariffId = tbl2.tariffId)) as maxValues
ON MinValues.TariffId = MaxValues.tariffId
and MinValues.RN = MaxValues.RN
order by MinValues.Date

結果:

1   2009-01-01 00:00:00.000 2009-01-02 00:00:00.000 1
3   2009-01-03 00:00:00.000 2009-01-03 00:00:00.000 2
4   2009-01-04 00:00:00.000 2009-01-05 00:00:00.000 3
6   2009-01-06 00:00:00.000 2009-01-07 00:00:00.000 1
8   2009-01-08 00:00:00.000 2009-01-08 00:00:00.000 3
9   2009-01-09 00:00:00.000 2009-01-11 00:00:00.000 4