如何生成一系列SQL Server中的日期如何生成一系列SQL Server中的日期(How to

标题并没有完全抓住了我的意思，这可能是重复的。

这里的长版本：给定一个客人的名字，他们的注册日期，以及他们的结账日期，我该如何生成一个行的每一天，他们是客人？

例如：鲍勃检查在7/14和7/17离开。我想要

('Bob', 7/14), ('Bob', 7/15), ('Bob', 7/16), ('Bob', 7/17)

我的结果。

谢谢！

Answer 1:

我认为，为这一特定目的的询问之下大约是使用专用的查找表一样有效。

DECLARE @start DATE, @end DATE;
SELECT @start = '20110714', @end = '20110717';

;WITH n AS 
(
  SELECT TOP (DATEDIFF(DAY, @start, @end) + 1) 
    n = ROW_NUMBER() OVER (ORDER BY [object_id])
  FROM sys.all_objects
)
SELECT 'Bob', DATEADD(DAY, n-1, @start)
FROM n;

结果：

Bob     2011-07-14
Bob     2011-07-15
Bob     2011-07-16
Bob     2011-07-17

想必你需要这个为一组，而不是一个单一的成员，所以这里是一个适应这种技术方式：

DECLARE @t TABLE
(
    Member NVARCHAR(32), 
    RegistrationDate DATE, 
    CheckoutDate DATE
);

INSERT @t SELECT N'Bob', '20110714', '20110717'
UNION ALL SELECT N'Sam', '20110712', '20110715'
UNION ALL SELECT N'Jim', '20110716', '20110719';

;WITH [range](d,s) AS 
(
  SELECT DATEDIFF(DAY, MIN(RegistrationDate), MAX(CheckoutDate))+1,
    MIN(RegistrationDate)
    FROM @t -- WHERE ?
),
n(d) AS
(
  SELECT DATEADD(DAY, n-1, (SELECT MIN(s) FROM [range]))
  FROM (SELECT ROW_NUMBER() OVER (ORDER BY [object_id])
  FROM sys.all_objects) AS s(n)
  WHERE n <= (SELECT MAX(d) FROM [range])
)
SELECT t.Member, n.d
FROM n CROSS JOIN @t AS t
WHERE n.d BETWEEN t.RegistrationDate AND t.CheckoutDate;
----------^^^^^^^ not many cases where I'd advocate between!

结果：

Member    d
--------  ----------
Bob       2011-07-14
Bob       2011-07-15
Bob       2011-07-16
Bob       2011-07-17
Sam       2011-07-12
Sam       2011-07-13
Sam       2011-07-14
Sam       2011-07-15
Jim       2011-07-16
Jim       2011-07-17
Jim       2011-07-18
Jim       2011-07-19

作为@Dems指出，这可以简化为：

;WITH natural AS 
(
  SELECT ROW_NUMBER() OVER (ORDER BY [object_id]) - 1 AS val 
  FROM sys.all_objects
) 
SELECT t.Member, d = DATEADD(DAY, natural.val, t.RegistrationDate) 
  FROM @t AS t INNER JOIN natural 
  ON natural.val <= DATEDIFF(DAY, t.RegistrationDate, t.CheckoutDate);

Answer 2:

我通常这样做对一些表中的使用技巧ROW_NUMBER（）。所以：

select t.name, dateadd(d, seq.seqnum, t.start_date)
from t left outer join
     (select row_number() over (order by (select NULL)) as seqnum
      from t
     ) seq
     on seqnum <= datediff(d, t.start_date, t.end_date)

对于NGF的云计算非常快，因为不需要计算或排序。但是，您需要确保该表是所有的时间跨度不够大。

Answer 3:

如果你有一个“理货”或“号码”表，生活GET真实这样的事情很简单。

 SELECT Member, DatePresent = DATEADD(dd,t.N,RegistrationDate)
   FROM @t 
  CROSS JOIN dbo.Tally t
  WHERE t.N BETWEEN 0 AND DATEDIFF(dd,RegistrationDate,CheckoutDate)
;

以下是如何建立一个“理货”表。

--===================================================================
--      Create a Tally table from 0 to 11000
--===================================================================
--===== Create and populate the Tally table on the fly.
 SELECT TOP 11001
        IDENTITY(INT,0,1) AS N
   INTO dbo.Tally
   FROM Master.sys.ALL_Columns ac1
  CROSS JOIN Master.sys.ALL_Columns ac2
;
--===== Add a CLUSTERED Primary Key to maximize performance
  ALTER TABLE dbo.Tally
    ADD CONSTRAINT PK_Tally_N 
        PRIMARY KEY CLUSTERED (N) WITH FILLFACTOR = 100
;
--===== Allow the general public to use it
  GRANT SELECT ON dbo.Tally TO PUBLIC
;
GO

关于什么是“理货”表是SQL的详细信息，以及它如何被用来取代尽管这算循环和热膨胀系数reursive的“隐藏RBAR”，请看下面的文章。

http://www.sqlservercentral.com/articles/T-SQL/62867/

Answer 4:

这可能为亚工作：

with mycte as
 (
     select cast('2000-01-01' as datetime) DateValue, 'Bob' as Name
     union all
     select DateValue + 1 ,'Bob' as Name
     from    mycte   
     where   DateValue + 1 < '2000-12-31'
 )
 select *
from    mycte
OPTION (MAXRECURSION 0)