Add Missing Date Range to Result Record Set - sql-server-2005

Question

I have a table containing the working hours for the company. We define the range of the dates and the number of hours for the range.
The number of working hours which is not in the defined range is 9.5 hours.
I want to have the non-defined range with the value of 9.5 added to the result record set.
how should I make the query to get this result?
The table definition and added records:
IF OBJECT_ID ('dbo.tbl_WorkingHours') IS NOT NULL
DROP TABLE dbo.tbl_WorkingHours
GO
CREATE TABLE dbo.tbl_WorkingHours
(
Startdate DATETIME NOT NULL,
EndDate DATETIME NOT NULL,
HoursDefined FLOAT NULL,
Description VARCHAR (255) NULL,
PRIMARY KEY (Startdate,EndDate)
)
INSERT INTO dbo.tbl_WorkingHours
(Startdate,EndDate,HoursDefined,Description)
VALUES
('3/4/2010','3/29/2010',7,'')
INSERT INTO dbo.tbl_WorkingHours
(Startdate,EndDate,HoursDefined,Description)
VALUES
('5/4/2010','5/29/2010',8,'')
The Result of Select * :
Startdate | EndDate | HoursDefined | Description
----------------------------------------------------
3/4/2010 3/29/2010 7
5/4/2010 5/29/2010 8
My desired record set:
Startdate | EndDate | HoursDefined | Description
----------------------------------------------------
1/1/1900 3/3/2010 9.5
3/4/2010 3/29/2010 7
3/30/2010 5/3/2010 9.5
5/4/2010 5/29/2010 8
5/30/2010 1/1/2050 9.5

Answer 1

The below assumes it is not possible to have overlapping ranges or two defined ranges that are contiguous but held as separate rows.
WITH wh AS
(
SELECT Startdate, EndDate, HoursDefined, Description,
ROW_NUMBER() over (order by startdate) as rn
FROM tbl_WorkingHours
)
SELECT Startdate, EndDate, HoursDefined, Description
FROM wh
UNION ALL
SELECT ISNULL(dateadd(day,1,w1.EndDate),'19000101'),
ISNULL(dateadd(day,-1,w2.StartDate),'20500101') , 9.5 AS HoursDefined,''
FROM wh w1 FULL OUTER JOIN wh w2
ON w2.rn = w1.rn+1
ORDER BY Startdate

Answer 2

try something like this:
DECLARE #tbl_WorkingHours table (Startdate DATETIME NOT NULL
,EndDate DATETIME NOT NULL
,HoursDefined FLOAT NULL
,Description VARCHAR (255) NULL
,PRIMARY KEY (Startdate,EndDate)
)
INSERT INTO #tbl_WorkingHours (Startdate,EndDate,HoursDefined,Description) VALUES ('3/4/2010','3/29/2010',7,'')
INSERT INTO #tbl_WorkingHours (Startdate,EndDate,HoursDefined,Description) VALUES ('5/4/2010','5/29/2010',8,'')
;WITH OrderedRows AS
( SELECT
Startdate,EndDate,HoursDefined,Description, ROW_NUMBER() OVER (ORDER BY Startdate,EndDate) AS RowNumber
FROM #tbl_WorkingHours
)
SELECT --before rows
CONVERT(datetime,'1/1/1900') AS Startdate,ISNULL(MIN(Startdate),CONVERT(datetime,'1/2/2050'))-1 AS EndDate,9.5 AS HoursDefined, CONVERT(VARCHAR (255),'') AS Description
FROM #tbl_WorkingHours
UNION ALL
SELECT --actual rows
Startdate,EndDate,HoursDefined,Description
FROM #tbl_WorkingHours
UNION ALL
SELECT --between rows
a.EndDate+1,b.Startdate-1,9.5,''
FROM OrderedRows a
INNER JOIN OrderedRows b ON a.RowNumber=b.RowNumber-1
UNION ALL
SELECT --after rows
ISNULL(MAX(EndDate),CONVERT(datetime,'1/1/2050')) AS Startdate,CONVERT(datetime,'1/2/2050')-1 AS EndDate,9.5 AS HoursDefined, CONVERT(VARCHAR (255),'') AS Description
FROM #tbl_WorkingHours
ORDER BY Startdate,EndDate
OUTPUT:
Startdate EndDate HoursDefined Description
----------------------- ----------------------- ---------------------- -----------
1900-01-01 00:00:00.000 2010-03-03 00:00:00.000 9.5
2010-03-04 00:00:00.000 2010-03-29 00:00:00.000 7
2010-03-30 00:00:00.000 2010-05-03 00:00:00.000 9.5
2010-05-04 00:00:00.000 2010-05-29 00:00:00.000 8
2010-05-29 00:00:00.000 2050-01-01 00:00:00.000 9.5
(5 row(s) affected)