0

I have a Dimension Table (as part of a data mart) with a DateTime field called 'Date'. I'd like to derive more info from Date though, so I have added additional fields for the number of the month , day number, etc ( these additional fields are currently un-populated.)

This is my SQL that attempts to populate 'MonthNumber' with the month number. It doesn't work though. Could anyone point me in the right direction here, I'm poor in SQL.

SELECT GETDATE() 'Date', MONTH(GETDATE()) 'MonthNumber'
FROM DimDate;
marc_s
  • 732,580
  • 175
  • 1,330
  • 1,459
Liam Fell
  • 1,308
  • 3
  • 21
  • 39
  • Can you be specific about what isn't working as expected, this is why we ask for sample data and expected output based on that sample, it often adds context. – G B Mar 17 '15 at 20:30
  • as a first suggestion, GETDATE() is the current datetime, so if you are wanting to extract the info from a date that already exists in `DimDate` then substitute that column name for the getdate() function – G B Mar 17 '15 at 20:32

1 Answers1

0

Most probably you are asking for system calendar that would be used in your DWH/BI or similar solution. Then there are plenty of working examples over internet. Just google for "system calendar sql server" and you'll find plenty of examples. There is copy/paste from another question: similiar question

CREATE SCHEMA Auxiliary
-- We put our auxiliary tables and stuff in a separate schema
-- One of the great new things in SQL Server 2005
go

CREATE FUNCTION Auxiliary.Computus
-- Computus (Latin for computation) is the calculation of the date of
-- Easter in the Christian calendar
-- http://en.wikipedia.org/wiki/Computus
-- I'm using the Meeus/Jones/Butcher Gregorian algorithm
(
    @Y INT -- The year we are calculating easter sunday for
)
RETURNS DATETIME
AS
BEGIN
DECLARE
@a INT,
@b INT,
@c INT,
@d INT,
@e INT,
@f INT,
@g INT,
@h INT,
@i INT,
@k INT,
@L INT,
@m INT

SET @a = @Y % 19
SET @b = @Y / 100
SET @c = @Y % 100
SET @d = @b / 4
SET @e = @b % 4
SET @f = (@b + 8) / 25
SET @g = (@b - @f + 1) / 3
SET @h = (19 * @a + @b - @d - @g + 15) % 30
SET @i = @c / 4
SET @k = @c % 4
SET @L = (32 + 2 * @e + 2 * @i - @h - @k) % 7
SET @m = (@a + 11 * @h + 22 * @L) / 451
RETURN(DATEADD(month, ((@h + @L - 7 * @m + 114) / 31)-1, cast(cast(@Y AS VARCHAR) AS Datetime)) + ((@h + @L - 7 * @m + 114) % 31))
END
GO


CREATE TABLE [Auxiliary].[Calendar] (
-- This is the calendar table
  [Date] datetime NOT NULL,
  [Year] int NOT NULL,
  [Quarter] int NOT NULL,
  [Month] int NOT NULL,
  [Week] int NOT NULL,
  [Day] int NOT NULL,
  [DayOfYear] int NOT NULL,
  [Weekday] int NOT NULL,
  [Fiscal_Year] int NOT NULL,
  [Fiscal_Quarter] int NOT NULL,
  [Fiscal_Month] int NOT NULL,
  [KindOfDay] varchar(10) NOT NULL,
  [Description] varchar(50) NULL,
  PRIMARY KEY CLUSTERED ([Date])
)
GO

ALTER TABLE [Auxiliary].[Calendar]
-- In Celkoish style I'm manic about constraints (Never use em ;-))
-- http://www.celko.com/

ADD CONSTRAINT [Calendar_ck] CHECK (  ([Year] > 1900)
AND ([Quarter] BETWEEN 1 AND 4)
AND ([Month] BETWEEN 1 AND 12)
AND ([Week]  BETWEEN 1 AND 53)
AND ([Day] BETWEEN 1 AND 31)
AND ([DayOfYear] BETWEEN 1 AND 366)
AND ([Weekday] BETWEEN 1 AND 7)
AND ([Fiscal_Year] > 1900)
AND ([Fiscal_Quarter] BETWEEN 1 AND 4)
AND ([Fiscal_Month] BETWEEN 1 AND 12)
AND ([KindOfDay] IN ('HOLIDAY', 'SATURDAY', 'SUNDAY', 'BANKDAY')))
GO




SET DATEFIRST 1;
-- I want my table to contain datedata acording to ISO 8601
-- http://en.wikipedia.org/wiki/ISO_8601
-- thus first day of a week is monday
WITH Dates(Date)
-- A recursive CTE that produce all dates between 1999 and 2020-12-31
AS
(
SELECT cast('1999' AS DateTime) Date -- SQL Server supports the ISO 8601 format so this is an unambigious shortcut for 1999-01-01
UNION ALL                            -- http://msdn2.microsoft.com/en-us/library/ms190977.aspx
SELECT (Date + 1) AS Date
FROM Dates
WHERE
Date < cast('2021' AS DateTime) -1
),

DatesAndThursdayInWeek(Date, Thursday)
-- The weeks can be found by counting the thursdays in a year so we find
-- the thursday in the week for a particular date
AS
(
SELECT
Date,
CASE DATEPART(weekday,Date)
WHEN 1 THEN Date + 3
WHEN 2 THEN Date + 2
WHEN 3 THEN Date + 1
WHEN 4 THEN Date
WHEN 5 THEN Date - 1
WHEN 6 THEN Date - 2
WHEN 7 THEN Date - 3
END AS Thursday
FROM Dates
),

Weeks(Week, Thursday)
-- Now we produce the weeknumers for the thursdays
-- ROW_NUMBER is new to SQL Server 2005
AS
(
SELECT ROW_NUMBER() OVER(partition by year(Date) order by Date) Week, Thursday
FROM DatesAndThursdayInWeek
WHERE DATEPART(weekday,Date) = 4
)
INSERT INTO Auxiliary.Calendar
SELECT
d.Date,
YEAR(d.Date) AS Year,
DATEPART(Quarter, d.Date) AS Quarter,
MONTH(d.Date) AS Month,
w.Week,
DAY(d.Date) AS Day,
DATEPART(DayOfYear, d.Date) AS DayOfYear,
DATEPART(Weekday, d.Date) AS Weekday,

-- Fiscal year may be different to the actual year in Norway the are the same
-- http://en.wikipedia.org/wiki/Fiscal_year
YEAR(d.Date) AS Fiscal_Year,
DATEPART(Quarter, d.Date) AS Fiscal_Quarter,
MONTH(d.Date) AS Fiscal_Month,

CASE
-- Holidays in Norway
-- For other countries and states: Wikipedia - List of holidays by country
-- http://en.wikipedia.org/wiki/List_of_holidays_by_country
    WHEN (DATEPART(DayOfYear, d.Date) = 1)          -- New Year's Day
    OR (d.Date = Auxiliary.Computus(YEAR(Date))-7)  -- Palm Sunday
    OR (d.Date = Auxiliary.Computus(YEAR(Date))-3)  -- Maundy Thursday
    OR (d.Date = Auxiliary.Computus(YEAR(Date))-2)  -- Good Friday
    OR (d.Date = Auxiliary.Computus(YEAR(Date)))    -- Easter Sunday
    OR (d.Date = Auxiliary.Computus(YEAR(Date))+39) -- Ascension Day
    OR (d.Date = Auxiliary.Computus(YEAR(Date))+49) -- Pentecost
    OR (d.Date = Auxiliary.Computus(YEAR(Date))+50) -- Whitmonday
    OR (MONTH(d.Date) = 5 AND DAY(d.Date) = 1)      -- Labour day
    OR (MONTH(d.Date) = 5 AND DAY(d.Date) = 17)     -- Constitution day
    OR (MONTH(d.Date) = 12 AND DAY(d.Date) = 25)    -- Cristmas day
    OR (MONTH(d.Date) = 12 AND DAY(d.Date) = 26)    -- Boxing day
    THEN 'HOLIDAY'
    WHEN DATEPART(Weekday, d.Date) = 6 THEN 'SATURDAY'
    WHEN DATEPART(Weekday, d.Date) = 7 THEN 'SUNDAY'
    ELSE 'BANKDAY'
END KindOfDay,
CASE
-- Description of holidays in Norway
    WHEN (DATEPART(DayOfYear, d.Date) = 1)            THEN 'New Year''s Day'
    WHEN (d.Date = Auxiliary.Computus(YEAR(Date))-7)  THEN 'Palm Sunday'
    WHEN (d.Date = Auxiliary.Computus(YEAR(Date))-3)  THEN 'Maundy Thursday'
    WHEN (d.Date = Auxiliary.Computus(YEAR(Date))-2)  THEN 'Good Friday'
    WHEN (d.Date = Auxiliary.Computus(YEAR(Date)))    THEN 'Easter Sunday'
    WHEN (d.Date = Auxiliary.Computus(YEAR(Date))+39) THEN 'Ascension Day'
    WHEN (d.Date = Auxiliary.Computus(YEAR(Date))+49) THEN 'Pentecost'
    WHEN (d.Date = Auxiliary.Computus(YEAR(Date))+50) THEN 'Whitmonday'
    WHEN (MONTH(d.Date) = 5 AND DAY(d.Date) = 1)      THEN 'Labour day'
    WHEN (MONTH(d.Date) = 5 AND DAY(d.Date) = 17)     THEN 'Constitution day'
    WHEN (MONTH(d.Date) = 12 AND DAY(d.Date) = 25)    THEN 'Cristmas day'
    WHEN (MONTH(d.Date) = 12 AND DAY(d.Date) = 26)    THEN 'Boxing day'
END Description

FROM DatesAndThursdayInWeek d
-- This join is for getting the week into the result set
     inner join Weeks w
     on d.Thursday = w.Thursday

OPTION(MAXRECURSION 0)
GO

CREATE FUNCTION Auxiliary.Numbers
(
@AFrom INT,
@ATo INT,
@AIncrement INT
)
RETURNS @RetNumbers TABLE
(
[Number] int PRIMARY KEY NOT NULL
)
AS
BEGIN
WITH Numbers(n)
AS
(
SELECT @AFrom AS n
UNION ALL
SELECT (n + @AIncrement) AS n
FROM Numbers
WHERE
n < @ATo
)
INSERT @RetNumbers
SELECT n from Numbers
OPTION(MAXRECURSION 0)
RETURN;
END
GO

CREATE FUNCTION Auxiliary.iNumbers
(
@AFrom INT,
@ATo INT,
@AIncrement INT
)
RETURNS TABLE
AS
RETURN(
WITH Numbers(n)
AS
(
SELECT @AFrom AS n
UNION ALL
SELECT (n + @AIncrement) AS n
FROM Numbers
WHERE
n < @ATo
)
SELECT n AS Number from Numbers
)
GO
Community
  • 1
  • 1
Dmitrij Kultasev
  • 5,447
  • 5
  • 44
  • 88
  • For what it is worth, using a recursive CTE to generate a list of numbers does not scale well at all, so the function for numbers in this is a poor one. For more information read the series [Generate a set or Sequence without loops](http://sqlperformance.com/2013/01/t-sql-queries/generate-a-set-1) – GarethD Mar 17 '15 at 20:55
  • 1
    Not much, but the function `Auxiliary.iNumbers` looks like it is set up for use more than once (otherwise why make a function?). In addition, since Stackoverflow is a very popular site where answers are viewed by many different people, it is possible someone will read this answer and not be aware how poorly a recursive CTE performs, use this numbers function then run in to issues. This is why even where performance is not an issue I think it is a good idea to use the best solution, rather than one that is just ok. – GarethD Mar 17 '15 at 21:18