Question

如果没有循环或游标，您如何获取日期间隔列表并将其转换为1和0的字符串，以便：

每个位代表从最小（所有日期）到最大（所有日期）
如果该日落在任何日期间隔内，则该位为1
如果该日没有落入任何间隔

例如，如果间隔是：

2011年1月1日至2011年1月1日
2011年4月4日至2011年5月5日

然后你编写的SQL应该输出11011.这是你可以使用的安装脚本：

declare @TimeSpan table
(
    start datetime
    ,finish datetime
)

-- this is a good data set, with overlapping and non-overlapping time spans
insert into @TimeSpan values ('02/02/2010', '02/02/2010')
insert into @TimeSpan values ('02/03/2010', '02/03/2010')
insert into @TimeSpan values ('02/04/2010', '02/05/2010')
insert into @TimeSpan values ('02/05/2010', '02/06/2010')
insert into @TimeSpan values ('02/07/2010', '02/09/2010')
insert into @TimeSpan values ('02/08/2010', '02/08/2010')
insert into @TimeSpan values ('02/08/2010', '02/10/2010')
insert into @TimeSpan values ('02/14/2010', '02/16/2010')

-- for this set of data, the output string would be 111111111000111

Answer 1

DECLARE @Result VARCHAR(MAX), @start DATETIME

SELECT @start= MIN(start) ,
       @Result =REPLICATE('0',1+DATEDIFF(DAY,MIN(start),MAX(finish)))
FROM @TimeSpan

SELECT @Result = STUFF(@Result,
                       DATEDIFF(DAY,@start,start)+1,
                       DATEDIFF(DAY,start,finish)+1,
                       REPLICATE('1',1+DATEDIFF(DAY,start,finish)))
FROM @TimeSpan 

SELECT @Result

Answer 2

我不得不使用递归CTE; - ）

DECLARE @BitString varchar(100);
Declare @minStart datetime
DECLARE @MaxEnd datetime
declare @RangeDates table
(
    start datetime
    ,finish datetime
)

-- this is a good data set, with overlapping and non-overlapping time spans
insert into @RangeDates values ('02/02/2010', '02/02/2010')
insert into @RangeDates values ('02/03/2010', '02/03/2010')
insert into @RangeDates values ('02/04/2010', '02/05/2010')
insert into @RangeDates values ('02/05/2010', '02/06/2010')
insert into @RangeDates values ('02/07/2010', '02/09/2010')
insert into @RangeDates values ('02/08/2010', '02/08/2010')
insert into @RangeDates values ('02/08/2010', '02/10/2010')
insert into @RangeDates values ('02/14/2010', '02/16/2010')

SELECT @minStart = MIN(start) FROM @RangeDates
SELECT @MaxEnd = MAX(finish) FROM @RangeDates

;WITH Dates AS (

        SELECT myDate = CONVERT(DateTime, @minStart), 
        CASE
            WHEN exists (SELECT * FROM @RangeDates where @minStart between start and finish) then '1'
            else '0'
        END as myBit
        UNION ALL
        SELECT myDate = DATEADD(DAY,1,myDate),
        CASE
            WHEN exists (SELECT * FROM @RangeDates where myDate between start and finish) then '1'
            else '0'
        END
        FROM Dates
        where myDate <= @MaxEnd
)

SELECT @BitString = COALESCE(@BitString,'') + myBit FROM Dates
SELECT @BitString

Answer 3

好的，这是我的解决方案。比其他计数表解决方案快一点，但不是很好。此外，它受限于转换为数字只允许较小的最小 - 最大日期范围。递归CTE比计数表更快是很奇怪的。计数表是否更好地扩展？

declare @Tally table
(
    N int identity(1,1),
    T bit
)

 insert into @Tally
 select TOP 11000 0 as T
   from master.dbo.SysColumns sc1, master.dbo.SysColumns sc2


declare @begin datetime = (select MIN(start) from @TimeSpan);
declare @end datetime = (select MAX(finish) from @TimeSpan);

with strings as
(
 select S.*
        ,
        '1'+
        REPLICATE('0', DATEDIFF(DAY, @begin, DATEADD(DAY,N-1,S.start)))+
        '1'+
        REPLICATE('0', DATEDIFF(DAY, DATEADD(DAY,N-1,S.start), @end)) task

   from @TimeSpan S
            inner join
        @Tally T                    ON DateAdd(DAY,T.N-1,S.start) <= S.finish
)

 select SUM(DISTINCT convert(numeric(38,0),task)) 
        - COUNT(DISTINCT task)*(convert(numeric(38,0), '1' + REPLICATE('0',DATEDIFF(d,@begin,@end)+1)))
   from strings

有趣的SQL拼图

3 个答案: