Question

我有一个名为Assignment的2列表。该表包含Person（nvarchar(20)）和Day（date）的分配，如下所示：

Person      Day
------------------
John    2011-05-23
John    2011-05-24
John    2011-05-25
John    2011-05-27
John    2011-05-28
John    2011-05-29
Anna    2011-05-02
Anna    2011-05-03
Anna    2011-05-06

我需要在有一系列相邻日期时提取日期范围。输出应该是每行的单个字符串值：

------------------
John    2011-05-23 - 2011-05-25
John    2011-05-27 - 2011-05-29
Anna    2011-05-02 - 2011-05-03
Anna    2011-05-06 - 2011-05-06

我尝试了分组然后

   CAST(min(Day) AS VARCHAR) + ' - ' + CAST(max(Day) AS VARCHAR)

但它无法正常工作。

欢迎任何建议。感谢。

Answer 1

declare @T table(Person nvarchar(20), [Day] date)

insert into @T values
('John',    '2011-05-23'),
('John',    '2011-05-24'),
('John',    '2011-05-25'),
('John',    '2011-05-27'),
('John',    '2011-05-28'),
('John',    '2011-05-29'),
('Anna',    '2011-05-02'),
('Anna',    '2011-05-03'),
('Anna',    '2011-05-06')


;WITH cte AS
(
SELECT *,
        DATEDIFF(DAY,0,[Day])-
        ROW_NUMBER() OVER (PARTITION BY Person ORDER BY [Day]) AS Grp
FROM @T  
)
SELECT Person, 
       MIN([Day]) AS DateFrom, 
       MAX([Day]) AS DateTo  
FROM cte 
GROUP BY Person, Grp

在SQL Server中聚合日期

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