Kdjykuj

I've got a bunch of financial reports, and we want to be able to pass them two inputs (year and quarter) as variables.

I'm doing it this way, but I really don't like it:

    declare @quarter int,

    @year int,

    @date date



    set @quarter = 4

    set @year = 2018





    set @date = cast(@year as varchar(4)) + '-01-01'

    set @date = dateadd(quarter, @quarter - 1, @date)





    print @date

Question What is the best way to reconstruct a date from integer inputs?

desired result:

    2018-10-01

Let me suggest to NOT use a date separator like '-' or '/', it deppends on regional settings, use YYYYMMDD format.

declare @quarter int,

    @year int,

    @date date



    set @quarter = 4

    set @year = 2018





    set @date = cast(@year as varchar(4)) + '0101'

    set @date = dateadd(quarter, 1 - 1, @date)

    print @date



    set @date = cast(@year as varchar(4)) + '0101'

    set @date = dateadd(quarter, 2 - 1, @date)

    print @date



    set @date = cast(@year as varchar(4)) + '0101'

    set @date = dateadd(quarter, 3 - 1, @date)

    print @date



    set @date = cast(@year as varchar(4)) + '0101'

    set @date = dateadd(quarter, 4 - 1, @date)

    print @date

2018-01-01

2018-04-01

2018-07-01

2018-10-01

db<>fiddle here

How about

declare @quarter int = 4

declare @year int = 2018



select datefromparts(@year,(@quarter-1)*3+1,1)

or if you're still using SQL 2008:

select dateadd(month,(@quarter-1)*3,dateadd(year, @year-2018,'20180101'))

You could Create a date dimension or calendar table in SQL Server and query it

--demo setup 

drop table if exists #dim

DECLARE @StartDate DATE = '20000101', @NumberOfYears INT = 30;



-- prevent set or regional settings from interfering with 

-- interpretation of dates / literals



SET DATEFIRST 7;

SET DATEFORMAT mdy;

SET LANGUAGE US_ENGLISH;



DECLARE @CutoffDate DATE = DATEADD(YEAR, @NumberOfYears, @StartDate);



-- this is just a holding table for intermediate calculations:



CREATE TABLE #dim

(

  [date]       DATE PRIMARY KEY, 

  [day]        AS DATEPART(DAY,      [date]),

  [month]      AS DATEPART(MONTH,    [date]),

  FirstOfMonth AS CONVERT(DATE, DATEADD(MONTH, DATEDIFF(MONTH, 0, [date]), 0)),

  [MonthName]  AS DATENAME(MONTH,    [date]),

  [week]       AS DATEPART(WEEK,     [date]),

  [ISOweek]    AS DATEPART(ISO_WEEK, [date]),

  [DayOfWeek]  AS DATEPART(WEEKDAY,  [date]),

  [quarter]    AS DATEPART(QUARTER,  [date]),

  [year]       AS DATEPART(YEAR,     [date]),

  FirstOfYear  AS CONVERT(DATE, DATEADD(YEAR,  DATEDIFF(YEAR,  0, [date]), 0)),

  Style112     AS CONVERT(CHAR(8),   [date], 112),

  Style101     AS CONVERT(CHAR(10),  [date], 101)

);



-- use the catalog views to generate as many rows as we need



INSERT #dim([date]) 

SELECT d

FROM

(

  SELECT d = DATEADD(DAY, rn - 1, @StartDate)

  FROM 

  (

    SELECT TOP (DATEDIFF(DAY, @StartDate, @CutoffDate)) 

      rn = ROW_NUMBER() OVER (ORDER BY s1.[object_id])

    FROM sys.all_objects AS s1

    CROSS JOIN sys.all_objects AS s2

    -- on my system this would support > 5 million days

    ORDER BY s1.[object_id]

  ) AS x

) AS y;



drop table if exists dbo.DateDimension



CREATE TABLE dbo.DateDimension

(

  --DateKey           INT         NOT NULL PRIMARY KEY,

  [Date]              DATE        NOT NULL,

  [Day]               TINYINT     NOT NULL,

  DaySuffix           CHAR(2)     NOT NULL,

  [Weekday]           TINYINT     NOT NULL,

  WeekDayName         VARCHAR(10) NOT NULL,

  IsWeekend           BIT         NOT NULL,

  IsHoliday           BIT         NOT NULL,

  HolidayText         VARCHAR(64) SPARSE,

  DOWInMonth          TINYINT     NOT NULL,

  [DayOfYear]         SMALLINT    NOT NULL,

  WeekOfMonth         TINYINT     NOT NULL,

  WeekOfYear          TINYINT     NOT NULL,

  ISOWeekOfYear       TINYINT     NOT NULL,

  [Month]             TINYINT     NOT NULL,

  [MonthName]         VARCHAR(10) NOT NULL,

  [Quarter]           TINYINT     NOT NULL,

  QuarterName         VARCHAR(6)  NOT NULL,

  [Year]              INT         NOT NULL,

  MMYYYY              CHAR(6)     NOT NULL,

  MonthYear           CHAR(7)     NOT NULL,

  FirstDayOfMonth     DATE        NOT NULL,

  LastDayOfMonth      DATE        NOT NULL,

  FirstDayOfQuarter   DATE        NOT NULL,

  LastDayOfQuarter    DATE        NOT NULL,

  FirstDayOfYear      DATE        NOT NULL,

  LastDayOfYear       DATE        NOT NULL,

  FirstDayOfNextMonth DATE        NOT NULL,

  FirstDayOfNextYear  DATE        NOT NULL

);

INSERT dbo.DateDimension WITH (TABLOCKX)

SELECT

  --DateKey     = CONVERT(INT, Style112),

  [Date]        = [date],

  [Day]         = CONVERT(TINYINT, [day]),

  DaySuffix     = CONVERT(CHAR(2), CASE WHEN [day] / 10 = 1 THEN 'th' ELSE 

                  CASE RIGHT([day], 1) WHEN '1' THEN 'st' WHEN '2' THEN 'nd' 

                  WHEN '3' THEN 'rd' ELSE 'th' END END),

  [Weekday]     = CONVERT(TINYINT, [DayOfWeek]),

  [WeekDayName] = CONVERT(VARCHAR(10), DATENAME(WEEKDAY, [date])),

  [IsWeekend]   = CONVERT(BIT, CASE WHEN [DayOfWeek] IN (1,7) THEN 1 ELSE 0 END),

  [IsHoliday]   = CONVERT(BIT, 0),

  HolidayText   = CONVERT(VARCHAR(64), NULL),

  [DOWInMonth]  = CONVERT(TINYINT, ROW_NUMBER() OVER 

                  (PARTITION BY FirstOfMonth, [DayOfWeek] ORDER BY [date])),

  [DayOfYear]   = CONVERT(SMALLINT, DATEPART(DAYOFYEAR, [date])),

  WeekOfMonth   = CONVERT(TINYINT, DENSE_RANK() OVER 

                  (PARTITION BY [year], [month] ORDER BY [week])),

  WeekOfYear    = CONVERT(TINYINT, [week]),

  ISOWeekOfYear = CONVERT(TINYINT, ISOWeek),

  [Month]       = CONVERT(TINYINT, [month]),

  [MonthName]   = CONVERT(VARCHAR(10), [MonthName]),

  [Quarter]     = CONVERT(TINYINT, [quarter]),

  QuarterName   = CONVERT(VARCHAR(6), CASE [quarter] WHEN 1 THEN 'First' 

                  WHEN 2 THEN 'Second' WHEN 3 THEN 'Third' WHEN 4 THEN 'Fourth' END), 

  [Year]        = [year],

  MMYYYY        = CONVERT(CHAR(6), LEFT(Style101, 2)    + LEFT(Style112, 4)),

  MonthYear     = CONVERT(CHAR(7), LEFT([MonthName], 3) + LEFT(Style112, 4)),

  FirstDayOfMonth     = FirstOfMonth,

  LastDayOfMonth      = MAX([date]) OVER (PARTITION BY [year], [month]),

  FirstDayOfQuarter   = MIN([date]) OVER (PARTITION BY [year], [quarter]),

  LastDayOfQuarter    = MAX([date]) OVER (PARTITION BY [year], [quarter]),

  FirstDayOfYear      = FirstOfYear,

  LastDayOfYear       = MAX([date]) OVER (PARTITION BY [year]),

  FirstDayOfNextMonth = DATEADD(MONTH, 1, FirstOfMonth),

  FirstDayOfNextYear  = DATEADD(YEAR,  1, FirstOfYear)

FROM #dim

OPTION (MAXDOP 1);

--solution

SELECT min(Date)

  FROM [Test].[dbo].[DateDimension]

  where [year] = 2018 and [Quarter]=4

| Date       |

|------------|

| 2018-10-01 |

I would avoid using strings at all but use date arithmetic combined with a known (or even unknown!) zero epoch.

DECLARE @epoch DATE = CONVERT(DATE, 0);

/* can't remember if you can cast straight from int to date, if not go via datetime*/



SET @date = DATEADD(MONTH, (@quarter-1)*3, DATEADD(YEAR, @year - YEAR(@epoch), @epoch));

This avoids string to date comparison which is messy, culture-dependent and expensive.