A common practice in Data Warehouses is to create a dimension (usually a table) with all possible dates.
You can create a table with all the dates in your database and retrieve the result by a simple query :
SELECT date FROM allDates WHERE date BETWWEN 20150401 AND 20150501;
The advantage of using this type of table is in the performance gain if you need to make large joins with this date range.
You can create this table using a script and if you wish you can insert more columns according to your need.
A sample script follows:
BEGIN TRY
DROP TABLE [dbo].[DimDate]
END TRY
BEGIN CATCH
/*No Action*/
END CATCH
/**********************************************************************************/
CREATE TABLE [dbo].[DimDate]
( [DateKey] INT primary key,
[Date] DATETIME,
[FullDateUK] CHAR(10), -- Date in dd-MM-yyyy format
[FullDateUSA] CHAR(10),-- Date in MM-dd-yyyy format
[DayOfMonth] VARCHAR(2), -- Field will hold day number of Month
[DaySuffix] VARCHAR(4), -- Apply suffix as 1st, 2nd ,3rd etc
[DayName] VARCHAR(9), -- Contains name of the day, Sunday, Monday
[DayOfWeekUSA] CHAR(1),-- First Day Sunday=1 and Saturday=7
[DayOfWeekUK] CHAR(1),-- First Day Monday=1 and Sunday=7
[DayOfWeekInMonth] VARCHAR(2), --1st Monday or 2nd Monday in Month
[DayOfWeekInYear] VARCHAR(2),
[DayOfQuarter] VARCHAR(3),
[DayOfYear] VARCHAR(3),
[WeekOfMonth] VARCHAR(1),-- Week Number of Month
[WeekOfQuarter] VARCHAR(2), --Week Number of the Quarter
[WeekOfYear] VARCHAR(2),--Week Number of the Year
[Month] VARCHAR(2), --Number of the Month 1 to 12
[MonthName] VARCHAR(9),--January, February etc
[MonthOfQuarter] VARCHAR(2),-- Month Number belongs to Quarter
[Quarter] CHAR(1),
[QuarterName] VARCHAR(9),--First,Second..
[Year] CHAR(4),-- Year value of Date stored in Row
[YearName] CHAR(7), --CY 2012,CY 2013
[MonthYear] CHAR(10), --Jan-2013,Feb-2013
[MMYYYY] CHAR(6),
[FirstDayOfMonth] DATE,
[LastDayOfMonth] DATE,
[FirstDayOfQuarter] DATE,
[LastDayOfQuarter] DATE,
[FirstDayOfYear] DATE,
[LastDayOfYear] DATE,
[IsHolidayUSA] BIT,-- Flag 1=National Holiday, 0-No National Holiday
[IsWeekday] BIT,-- 0=Week End ,1=Week Day
[HolidayUSA] VARCHAR(50),--Name of Holiday in US
[IsHolidayUK] BIT Null,-- Flag 1=National Holiday, 0-No National Holiday
[HolidayUK] VARCHAR(50) Null --Name of Holiday in UK
)
GO
/********************************************************************************************/
--Specify Start Date and End date here
--Value of Start Date Must be Less than Your End Date
DECLARE @StartDate DATETIME = '01/01/2013' --Starting value of Date Range
DECLARE @EndDate DATETIME = '01/01/2018' --End Value of Date Range
--Temporary Variables To Hold the Values During Processing of Each Date of Year
DECLARE
@DayOfWeekInMonth INT,
@DayOfWeekInYear INT,
@DayOfQuarter INT,
@WeekOfMonth INT,
@CurrentYear INT,
@CurrentMonth INT,
@CurrentQuarter INT
/*Table Data type to store the day of week count for the month and year*/
DECLARE @DayOfWeek TABLE (DOW INT, MonthCount INT, QuarterCount INT, YearCount INT)
INSERT INTO @DayOfWeek VALUES (1, 0, 0, 0)
INSERT INTO @DayOfWeek VALUES (2, 0, 0, 0)
INSERT INTO @DayOfWeek VALUES (3, 0, 0, 0)
INSERT INTO @DayOfWeek VALUES (4, 0, 0, 0)
INSERT INTO @DayOfWeek VALUES (5, 0, 0, 0)
INSERT INTO @DayOfWeek VALUES (6, 0, 0, 0)
INSERT INTO @DayOfWeek VALUES (7, 0, 0, 0)
--Extract and assign various parts of Values from Current Date to Variable
DECLARE @CurrentDate AS DATETIME = @StartDate
SET @CurrentMonth = DATEPART(MM, @CurrentDate)
SET @CurrentYear = DATEPART(YY, @CurrentDate)
SET @CurrentQuarter = DATEPART(QQ, @CurrentDate)
/********************************************************************************************/
--Proceed only if Start Date(Current date ) is less than End date you specified above
WHILE @CurrentDate < @EndDate
BEGIN
/*Begin day of week logic*/
/*Check for Change in Month of the Current date if Month changed then
Change variable value*/
IF @CurrentMonth != DATEPART(MM, @CurrentDate)
BEGIN
UPDATE @DayOfWeek
SET MonthCount = 0
SET @CurrentMonth = DATEPART(MM, @CurrentDate)
END
/* Check for Change in Quarter of the Current date if Quarter changed then change
Variable value*/
IF @CurrentQuarter != DATEPART(QQ, @CurrentDate)
BEGIN
UPDATE @DayOfWeek
SET QuarterCount = 0
SET @CurrentQuarter = DATEPART(QQ, @CurrentDate)
END
/* Check for Change in Year of the Current date if Year changed then change
Variable value*/
IF @CurrentYear != DATEPART(YY, @CurrentDate)
BEGIN
UPDATE @DayOfWeek
SET YearCount = 0
SET @CurrentYear = DATEPART(YY, @CurrentDate)
END
-- Set values in table data type created above from variables
UPDATE @DayOfWeek
SET
MonthCount = MonthCount + 1,
QuarterCount = QuarterCount + 1,
YearCount = YearCount + 1
WHERE DOW = DATEPART(DW, @CurrentDate)
SELECT
@DayOfWeekInMonth = MonthCount,
@DayOfQuarter = QuarterCount,
@DayOfWeekInYear = YearCount
FROM @DayOfWeek
WHERE DOW = DATEPART(DW, @CurrentDate)
/*End day of week logic*/
/* Populate Your Dimension Table with values*/
INSERT INTO [dbo].[DimDate]
SELECT
CONVERT (char(8),@CurrentDate,112) as DateKey,
@CurrentDate AS Date,
CONVERT (char(10),@CurrentDate,103) as FullDateUK,
CONVERT (char(10),@CurrentDate,101) as FullDateUSA,
DATEPART(DD, @CurrentDate) AS DayOfMonth,
--Apply Suffix values like 1st, 2nd 3rd etc..
CASE
WHEN DATEPART(DD,@CurrentDate) IN (11,12,13) _
THEN CAST(DATEPART(DD,@CurrentDate) AS VARCHAR) + 'th'
WHEN RIGHT(DATEPART(DD,@CurrentDate),1) = 1 _
THEN CAST(DATEPART(DD,@CurrentDate) AS VARCHAR) + 'st'
WHEN RIGHT(DATEPART(DD,@CurrentDate),1) = 2 _
THEN CAST(DATEPART(DD,@CurrentDate) AS VARCHAR) + 'nd'
WHEN RIGHT(DATEPART(DD,@CurrentDate),1) = 3 _
THEN CAST(DATEPART(DD,@CurrentDate) AS VARCHAR) + 'rd'
ELSE CAST(DATEPART(DD,@CurrentDate) AS VARCHAR) + 'th'
END AS DaySuffix,
DATENAME(DW, @CurrentDate) AS DayName,
DATEPART(DW, @CurrentDate) AS DayOfWeekUSA,
-- check for day of week as Per US and change it as per UK format
CASE DATEPART(DW, @CurrentDate)
WHEN 1 THEN 7
WHEN 2 THEN 1
WHEN 3 THEN 2
WHEN 4 THEN 3
WHEN 5 THEN 4
WHEN 6 THEN 5
WHEN 7 THEN 6
END
AS DayOfWeekUK,
@DayOfWeekInMonth AS DayOfWeekInMonth,
@DayOfWeekInYear AS DayOfWeekInYear,
@DayOfQuarter AS DayOfQuarter,
DATEPART(DY, @CurrentDate) AS DayOfYear,
DATEPART(WW, @CurrentDate) + 1 - DATEPART(WW, CONVERT(VARCHAR, _
DATEPART(MM, @CurrentDate)) + '/1/' + CONVERT(VARCHAR, _
DATEPART(YY, @CurrentDate))) AS WeekOfMonth,
(DATEDIFF(DD, DATEADD(QQ, DATEDIFF(QQ, 0, @CurrentDate), 0), _
@CurrentDate) / 7) + 1 AS WeekOfQuarter,
DATEPART(WW, @CurrentDate) AS WeekOfYear,
DATEPART(MM, @CurrentDate) AS Month,
DATENAME(MM, @CurrentDate) AS MonthName,
CASE
WHEN DATEPART(MM, @CurrentDate) IN (1, 4, 7, 10) THEN 1
WHEN DATEPART(MM, @CurrentDate) IN (2, 5, 8, 11) THEN 2
WHEN DATEPART(MM, @CurrentDate) IN (3, 6, 9, 12) THEN 3
END AS MonthOfQuarter,
DATEPART(QQ, @CurrentDate) AS Quarter,
CASE DATEPART(QQ, @CurrentDate)
WHEN 1 THEN 'First'
WHEN 2 THEN 'Second'
WHEN 3 THEN 'Third'
WHEN 4 THEN 'Fourth'
END AS QuarterName,
DATEPART(YEAR, @CurrentDate) AS Year,
'CY ' + CONVERT(VARCHAR, DATEPART(YEAR, @CurrentDate)) AS YearName,
LEFT(DATENAME(MM, @CurrentDate), 3) + '-' + CONVERT(VARCHAR, _
DATEPART(YY, @CurrentDate)) AS MonthYear,
RIGHT('0' + CONVERT(VARCHAR, DATEPART(MM, @CurrentDate)),2) + _
CONVERT(VARCHAR, DATEPART(YY, @CurrentDate)) AS MMYYYY,
CONVERT(DATETIME, CONVERT(DATE, DATEADD(DD, - (DATEPART(DD, _
@CurrentDate) - 1), @CurrentDate))) AS FirstDayOfMonth,
CONVERT(DATETIME, CONVERT(DATE, DATEADD(DD, - (DATEPART(DD, _
(DATEADD(MM, 1, @CurrentDate)))), DATEADD(MM, 1, _
@CurrentDate)))) AS LastDayOfMonth,
DATEADD(QQ, DATEDIFF(QQ, 0, @CurrentDate), 0) AS FirstDayOfQuarter,
DATEADD(QQ, DATEDIFF(QQ, -1, @CurrentDate), -1) AS LastDayOfQuarter,
CONVERT(DATETIME, '01/01/' + CONVERT(VARCHAR, DATEPART(YY, _
@CurrentDate))) AS FirstDayOfYear,
CONVERT(DATETIME, '12/31/' + CONVERT(VARCHAR, DATEPART(YY, _
@CurrentDate))) AS LastDayOfYear,
NULL AS IsHolidayUSA,
CASE DATEPART(DW, @CurrentDate)
WHEN 1 THEN 0
WHEN 2 THEN 1
WHEN 3 THEN 1
WHEN 4 THEN 1
WHEN 5 THEN 1
WHEN 6 THEN 1
WHEN 7 THEN 0
END AS IsWeekday,
NULL AS HolidayUSA, Null, Null
SET @CurrentDate = DATEADD(DD, 1, @CurrentDate)
END
/*******************************************************************************************/
/* Update HOLIDAY fields of UK as per Govt. Declaration of National Holiday ****/
-- Good Friday April 18
UPDATE [dbo].[DimDate]
SET HolidayUK = 'Good Friday'
WHERE [Month] = 4 AND [DayOfMonth] = 18
-- Easter Monday April 21
UPDATE [dbo].[DimDate]
SET HolidayUK = 'Easter Monday'
WHERE [Month] = 4 AND [DayOfMonth] = 21
-- Early May Bank Holiday May 5
UPDATE [dbo].[DimDate]
SET HolidayUK = 'Early May Bank Holiday'
WHERE [Month] = 5 AND [DayOfMonth] = 5
-- Spring Bank Holiday May 26
UPDATE [dbo].[DimDate]
SET HolidayUK = 'Spring Bank Holiday'
WHERE [Month] = 5 AND [DayOfMonth] = 26
-- Summer Bank Holiday August 25
UPDATE [dbo].[DimDate]
SET HolidayUK = 'Summer Bank Holiday'
WHERE [Month] = 8 AND [DayOfMonth] = 25
-- Boxing Day December 26
UPDATE [dbo].[DimDate]
SET HolidayUK = 'Boxing Day'
WHERE [Month] = 12 AND [DayOfMonth] = 26
--CHRISTMAS
UPDATE [dbo].[DimDate]
SET HolidayUK = 'Christmas Day'
WHERE [Month] = 12 AND [DayOfMonth] = 25
--New Years Day
UPDATE [dbo].[DimDate]
SET HolidayUK = 'New Year''s Day'
WHERE [Month] = 1 AND [DayOfMonth] = 1
--Update flag for UK Holidays 1= Holiday, 0=No Holiday
UPDATE [dbo].[DimDate]
SET IsHolidayUK = CASE WHEN HolidayUK IS NULL _
THEN 0 WHEN HolidayUK IS NOT NULL THEN 1 END
/*Update HOLIDAY Field of USA In dimension*/
/*THANKSGIVING - Fourth THURSDAY in November*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'Thanksgiving Day'
WHERE
[Month] = 11
AND [DayOfWeekUSA] = 'Thursday'
AND DayOfWeekInMonth = 4
/*CHRISTMAS*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'Christmas Day'
WHERE [Month] = 12 AND [DayOfMonth] = 25
/*4th of July*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'Independance Day'
WHERE [Month] = 7 AND [DayOfMonth] = 4
/*New Years Day*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'New Year''s Day'
WHERE [Month] = 1 AND [DayOfMonth] = 1
/*Memorial Day - Last Monday in May*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'Memorial Day'
FROM [dbo].[DimDate]
WHERE DateKey IN
(
SELECT
MAX(DateKey)
FROM [dbo].[DimDate]
WHERE
[MonthName] = 'May'
AND [DayOfWeekUSA] = 'Monday'
GROUP BY
[Year],
[Month]
)
/*Labor Day - First Monday in September*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'Labor Day'
FROM [dbo].[DimDate]
WHERE DateKey IN
(
SELECT
MIN(DateKey)
FROM [dbo].[DimDate]
WHERE
[MonthName] = 'September'
AND [DayOfWeekUSA] = 'Monday'
GROUP BY
[Year],
[Month]
)
/*Valentine's Day*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'Valentine''s Day'
WHERE
[Month] = 2
AND [DayOfMonth] = 14
/*Saint Patrick's Day*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'Saint Patrick''s Day'
WHERE
[Month] = 3
AND [DayOfMonth] = 17
/*Martin Luthor King Day - Third Monday in January starting in 1983*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'Martin Luthor King Jr Day'
WHERE
[Month] = 1
AND [DayOfWeekUSA] = 'Monday'
AND [Year] >= 1983
AND DayOfWeekInMonth = 3
/*President's Day - Third Monday in February*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'President''s Day'
WHERE
[Month] = 2
AND [DayOfWeekUSA] = 'Monday'
AND DayOfWeekInMonth = 3
/*Mother's Day - Second Sunday of May*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'Mother''s Day'
WHERE
[Month] = 5
AND [DayOfWeekUSA] = 'Sunday'
AND DayOfWeekInMonth = 2
/*Father's Day - Third Sunday of June*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'Father''s Day'
WHERE
[Month] = 6
AND [DayOfWeekUSA] = 'Sunday'
AND DayOfWeekInMonth = 3
/*Halloween 10/31*/
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'Halloween'
WHERE
[Month] = 10
AND [DayOfMonth] = 31
/*Election Day - The first Tuesday after the first Monday in November*/
BEGIN
DECLARE @Holidays TABLE (ID INT IDENTITY(1,1), _
DateID int, Week TINYINT, YEAR CHAR(4), DAY CHAR(2))
INSERT INTO @Holidays(DateID, [Year],[Day])
SELECT
DateKey,
[Year],
[DayOfMonth]
FROM [dbo].[DimDate]
WHERE
[Month] = 11
AND [DayOfWeekUSA] = 'Monday'
ORDER BY
YEAR,
DayOfMonth
DECLARE @CNTR INT, @POS INT, @STARTYEAR INT, @ENDYEAR INT, @MINDAY INT
SELECT
@CURRENTYEAR = MIN([Year])
, @STARTYEAR = MIN([Year])
, @ENDYEAR = MAX([Year])
FROM @Holidays
WHILE @CURRENTYEAR <= @ENDYEAR
BEGIN
SELECT @CNTR = COUNT([Year])
FROM @Holidays
WHERE [Year] = @CURRENTYEAR
SET @POS = 1
WHILE @POS <= @CNTR
BEGIN
SELECT @MINDAY = MIN(DAY)
FROM @Holidays
WHERE
[Year] = @CURRENTYEAR
AND [Week] IS NULL
UPDATE @Holidays
SET [Week] = @POS
WHERE
[Year] = @CURRENTYEAR
AND [Day] = @MINDAY
SELECT @POS = @POS + 1
END
SELECT @CURRENTYEAR = @CURRENTYEAR + 1
END
UPDATE [dbo].[DimDate]
SET HolidayUSA = 'Election Day'
FROM [dbo].[DimDate] DT
JOIN @Holidays HL ON (HL.DateID + 1) = DT.DateKey
WHERE
[Week] = 1
END
--set flag for USA holidays in Dimension
UPDATE [dbo].[DimDate]
SET IsHolidayUSA = CASE WHEN HolidayUSA IS NULL THEN 0 WHEN HolidayUSA IS NOT NULL THEN 1 END
/*****************************************************************************************/
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