('Bob', 7/14), ('Bob', 7/15), ('Bob', 7/16), ('Bob', 7/17)
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
假设您需要将其作为一组使用，而不是单个成员，因此这里有一种适应此技术的方法：
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
正如 @Dems 指出的那样，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);
WHERE n < = (SELECT MAX())，这意味着这可以进一步简化... WITH natural AS (SELECT ROW_NUMBER() OVER (ORDER BY id) - 1 AS val FROM sys.objects) SELECT t.Member, DATEADD(DAY, natural.val, t.start) FROM @t AS t INNER JOIN natural ON natural.val <= DATEDIFF(DAY, t.start, t.end) [但即便如此，一个直接查找表仍然至少会使用更少的CPU周期。] - MatBailie我通常使用row_number()函数在某个表上实现此操作。因此：
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)
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)
;
--===================================================================
-- 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
如果您想了解SQL中“Tally”表的含义以及如何使用它来替代While循环和递归CTE中的“Hidden RBAR”进行计数，请参阅以下文章。
这可能适合你：
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)
WHERE calendar.date >= user.start_date AND calendar.date <= user.leave_date您可以使用循环或递归查询生成集合，但它们永远不如使用查找表快速。 - MatBailie