I can do it with loop, but if many day is slow. So I need do without loop.
Here is my code:
DECLARE
#FRDT date = '01-SEP-2019'
,#TODT date = '30-SEP-2019'
,#N int
,#SUN int = 0
,#MON int = 0
,#TUE int = 0
,#WED int = 0
,#THU int = 0
,#FRI int = 0
,#SAT int = 0
WHILE #FRDT <= #TODT
BEGIN
SET #N = DATEPART(WEEKDAY, #FRDT)
IF #N = 1
SET #SUN = #SUN + 1
ELSE IF #N = 2
SET #MON = #MON + 1
ELSE IF #N = 3
SET #TUE = #TUE + 1
ELSE IF #N = 4
SET #WED = #WED + 1
ELSE IF #N = 5
SET #THU = #THU + 1
ELSE IF #N = 6
SET #FRI = #FRI + 1
ELSE IF #N = 7
SET #SAT = #SAT + 1
SET #FRDT = DATEADD(DAY, 1, #FRDT)
END
SELECT 1 AS [NO], 'Sunday' AS [DAYNAME], #SUN AS [NUMBEROFDAY]
UNION SELECT 2, 'Monday', #MON
UNION SELECT 3, 'Tuesday', #TUE
UNION SELECT 4, 'Wednesday', #WED
UNION SELECT 5, 'Thursday', #THU
UNION SELECT 6, 'Friday', #FRI
I want to result like code above, but not use loop for better performance.
The date range is 30 days, dividing by 7 gives quotient 4 and remainder 2.
So every day of the week gets 4 and two days need an additional one. These are the ones corresponding to #start_date and the following day in this case.
SQL to implement this approach is below (demo)
SELECT DATENAME(WEEKDAY,base_date),
quotient + IIF(Nums.N < remainder, 1, 0)
FROM (VALUES
(0),
(1),
(2),
(3),
(4),
(5),
(6)) Nums(N)
CROSS APPLY(SELECT 1 + DATEDIFF(DAY,#start_date,#end_date)) DC(day_count)
CROSS APPLY(SELECT DATEADD(DAY, Nums.N, #start_date), day_count/7, day_count% 7) D(base_date, quotient, remainder)
ORDER BY DATEPART(DW,base_date)
You can do it with using recursive CTE as below-
DECLARE #start_date DATE= '01-SEP-2019', #end_date DATE= '30-SEP-2019';
WITH cte
AS (
SELECT #start_date AS date_
UNION ALL
SELECT CAST(DATEADD(day, 1, date_) AS DATE)
FROM cte
WHERE date_ < #end_date
)
SELECT DATEPART(DW,date_) No,
DATENAME(DW,date_) Day_Name,
COUNT(*) Num_Day
FROM cte
GROUP BY DATEPART(DW,date_),DATENAME(DW,date_)
ORDER BY DATEPART(DW,date_)
OPTION(MAXRECURSION 0);
Output-
No Day_Name Num_Day
1 Sunday 5
2 Monday 5
3 Tuesday 4
4 Wednesday 4
5 Thursday 4
6 Friday 4
7 Saturday 4
For such situation you need to have a Number table or Date Table.
In my example I am using a Number table. You can create number table anyway you want and it will help in many situations.
Create Table tblNumber(Number int primary key)
insert into tblNumber (Number) values(1),(2)...... till thousands or millions
Edit: You could generate the numbers for this number table using:
INSERT INTO tblNumber
SELECT TOP 100000 ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) AS [N]
FROM dbo.syscolumns tb1,dbo.syscolumns tb2
Keep this table permanently as it is useful.
DECLARE #FromDT DATETIME= '2019-09-01';
DECLARE #ToDT DATETIME= '2019-09-30';
SELECT COUNT(*), wkday
FROM
(
SELECT DATEname(weekday, DATEADD(day, number, #FromDT)) wkday
FROM tblNumber
WHERE number BETWEEN DATEPART(day, #FromDT) AND DATEPART(day, #ToDT)
) tbl
GROUP BY wkday;
If you have a Date table then it is more efficient in this situation.
I have this code:
cast( DateDiff( MINUTE, S.PlannedStartDateTime, S.PlannedEndDateTime) as decimal (12,6)) / 60 else null end) BasicHours
which brings back the date time as decimal i.e. 31.416666, but this really needs to be 31hr 25mins
How can my code display the correct date format?
Yet another option.
Example
Declare #YourTable table (id int,StartTime datetime,EndTime datetime)
Insert Into #YourTable values
(1,'2017-01-01 20:30:15','2017-01-05 22:58:35'),
(2,'2017-01-01 09:00:00','2017-01-01 17:00:00'),
(3,'2017-01-01 09:00:00','2017-01-01 09:05:00')
Select A.ID
,Duration = concat(Seconds/3600,'hr ',Seconds%3600/60,'mins')
From #YourTable A
Cross Apply (values (DateDiff(SECOND,StartTime,EndTime))) B (Seconds)
Returns
ID Duration
1 98hr 28mins
2 8hr 0mins
3 0hr 5mins
EDIT if you don't want the CROSS APPLY
Select A.ID
,Duration = concat(DateDiff(SECOND,StartTime,EndTime)/3600,'hr ',DateDiff(SECOND,StartTime,EndTime)%3600/60,'mins')
From #YourTable A
One Should Note:, there is a limitation ... the max value of an INT (or 2,147,483,647). So provided your span does not exceed:
Years Months Days Hours Minutes Seconds
68 0 19 3 14 7
This is my version of Itzik Ben Gan's DATEDIFFPARTS function
CREATE FUNCTION dbo.tfn_DateDiffParts
/* =======================================================================================================
04/06/2017 JL, Created.
Code based off of a similar function created by Itzik Ben-Gan.
(http://sqlmag.com/sql-server/how-compute-date-and-time-difference-parts)
======================================================================================================= */
(
#dt1 AS DATETIME2(7),
#dt2 AS DATETIME2(7)
)
RETURNS TABLE WITH SCHEMABINDING AS
RETURN
SELECT
DateDiffParts = CONCAT(
CAST(V.yy AS VARCHAR(10)) + L.yy,
CAST(V.mm AS VARCHAR(10)) + L.mm,
CAST(V.dd AS VARCHAR(10)) + L.dd,
CAST(V.hh AS VARCHAR(10)) + L.hh,
CAST(V.mi AS VARCHAR(10)) + L.mi,
CAST(V.ss AS VARCHAR(10)) + L.ss
)
FROM
( VALUES (
CASE WHEN #dt1 > #dt2 THEN #dt2 ELSE #dt1 END,
CASE WHEN #dt1 > #dt2 THEN #dt1 ELSE #dt2 END
)
) D (dt1, dt2)
CROSS APPLY ( VALUES (
CAST(D.dt1 AS TIME),
CAST(D.dt2 AS TIME),
DATEDIFF(yy, D.dt1, D.dt2),
DATEDIFF(mm, D.dt1, D.dt2),
DATEDIFF(dd, D.dt1, D.dt2)
)
) A1 (t1, t2, yydiff, mmdiff, dddiff)
CROSS APPLY ( VALUES (
CASE WHEN DATEADD(yy, A1.yydiff, D.dt1) > D.dt2 THEN 1 ELSE 0 END,
CASE WHEN DATEADD(mm, A1.mmdiff, D.dt1) > D.dt2 THEN 1 ELSE 0 END,
CASE WHEN DATEADD(dd, A1.dddiff, D.dt1) > D.dt2 THEN 1 ELSE 0 END
)
) A2 (subyy, submm, subdd)
CROSS APPLY ( VALUES (
CAST(86400000000000 AS BIGINT) * A2.subdd
+ (CAST(1000000000 AS BIGINT) * DATEDIFF(ss, '00:00', A1.t2) + DATEPART(ns, A1.t2))
- (CAST(1000000000 AS BIGINT) * DATEDIFF(ss, '00:00', A1.t1) + DATEPART(ns, A1.t1))
)
) A3 (nsdiff)
CROSS APPLY ( VALUES (
A1.yydiff - A2.subyy,
(A1.mmdiff - A2.submm) % 12,
DATEDIFF(DAY, DATEADD(mm, A1.mmdiff - A2.submm,D.dt1), D.dt2) - A2.subdd,
A3.nsdiff / CAST(3600000000000 AS BIGINT),
A3.nsdiff / CAST(60000000000 AS BIGINT) % 60,
CAST(A3.nsdiff / 1000000000.0 % 60.0 AS DECIMAL(9,1))
)
) V (yy, mm, dd, hh, mi, ss)
CROSS APPLY ( VALUES (
CASE
WHEN V.yy > 1 THEN ' years, '
WHEN V.yy > 0 THEN ' year, '
END,
CASE
WHEN V.mm > 1 THEN ' months, '
WHEN V.mm > 0 THEN ' month, '
WHEN V.yy > 0 THEN ' months, '
END,
CASE
WHEN V.dd > 1 THEN ' days, '
WHEN V.dd > 0 THEN ' day, '
WHEN V.yy > 0 OR V.mm > 0 THEN ' days, '
END,
CASE
WHEN V.hh > 1 THEN ' hours, '
WHEN V.hh > 0 THEN ' hour, '
WHEN V.yy > 0 OR V.mm > 0 OR V.dd > 0 THEN ' hours, '
END,
CASE
WHEN V.mi > 1 THEN ' mins, '
WHEN V.mi > 0 THEN ' min, '
WHEN V.yy > 0 OR V.mm > 0 OR V.dd > 0 OR V.hh > 0 THEN ' mins, '
END,
CASE
WHEN V.ss > 1 THEN ' secs'
WHEN V.ss > 0 THEN ' sec'
WHEN V.yy > 0 OR V.mm > 0 OR V.dd > 0 OR V.hh > 0 OR V.mi > 0 THEN ' secs'
END
)
) L (yy, mm, dd, hh, mi, ss);
GO
Sample query...
SELECT
ddp.DateDiffParts
FROM
dbo.tfn_DateDiffParts('2017-06-01 08:22:11.12345', '2017-06-02 11:30:25.32145') ddp;
And the function output...
DateDiffParts
--------------------------------------------------------------------------------------------------------
1 day, 3 hours, 8 mins, 14.2 secs
you can use below query to get your result -
select CAST (CONCAT( datediff(HH,'2017-09-05 21:55:00','2017-09-07 08:16:00') , '.' , 60- datediff(MINUTE,'2017-09-05 21:55:00','2017-09-07 08:16:00')%60) as decimal (12,6))
--OUTPUT
35.390000
I want to calculate the number of working days between 2 given dates. For example if I want to calculate the working days between 2013-01-10 and 2013-01-15, the result must be 3 working days (I don't take into consideration the last day in that interval and I subtract the Saturdays and Sundays). I have the following code that works for most of the cases, except the one in my example.
SELECT (DATEDIFF(day, '2013-01-10', '2013-01-15'))
- (CASE WHEN DATENAME(weekday, '2013-01-10') = 'Sunday' THEN 1 ELSE 0 END)
- (CASE WHEN DATENAME(weekday, DATEADD(day, -1, '2013-01-15')) = 'Saturday' THEN 1 ELSE 0 END)
How can I accomplish this? Do I have to go through all the days and check them? Or is there an easy way to do this.
Please, please, please use a calendar table. SQL Server doesn't know anything about national holidays, company events, natural disasters, etc. A calendar table is fairly easy to build, takes an extremely small amount of space, and will be in memory if it is referenced enough.
Here is an example that creates a calendar table with 30 years of dates (2000 -> 2029) but requires only 200 KB on disk (136 KB if you use page compression). That is almost guaranteed to be less than the memory grant required to process some CTE or other set at runtime.
CREATE TABLE dbo.Calendar
(
dt DATE PRIMARY KEY, -- use SMALLDATETIME if < SQL Server 2008
IsWorkDay BIT
);
DECLARE #s DATE, #e DATE;
SELECT #s = '2000-01-01' , #e = '2029-12-31';
INSERT dbo.Calendar(dt, IsWorkDay)
SELECT DATEADD(DAY, n-1, '2000-01-01'), 1
FROM
(
SELECT TOP (DATEDIFF(DAY, #s, #e)+1) ROW_NUMBER()
OVER (ORDER BY s1.[object_id])
FROM sys.all_objects AS s1
CROSS JOIN sys.all_objects AS s2
) AS x(n);
SET DATEFIRST 1;
-- weekends
UPDATE dbo.Calendar SET IsWorkDay = 0
WHERE DATEPART(WEEKDAY, dt) IN (6,7);
-- Christmas
UPDATE dbo.Calendar SET IsWorkDay = 0
WHERE MONTH(dt) = 12
AND DAY(dt) = 25
AND IsWorkDay = 1;
-- continue with other holidays, known company events, etc.
Now the query you're after is quite simple to write:
SELECT COUNT(*) FROM dbo.Calendar
WHERE dt >= '20130110'
AND dt < '20130115'
AND IsWorkDay = 1;
More info on calendar tables:
http://web.archive.org/web/20070611150639/http://sqlserver2000.databases.aspfaq.com/why-should-i-consider-using-an-auxiliary-calendar-table.html
More info on generating sets without loops:
http://www.sqlperformance.com/tag/date-ranges
Also beware of little things like relying on the English output of DATENAME. I've seen several applications break because some users had a different language setting, and if you're relying on WEEKDAY be sure you set your DATEFIRST setting appropriately...
For stuff like this i tend to maintain a calendar table that also includes bank holidays etc.
The script i use for this is as follows (Note that i didnt write it # i forget where i found it)
SET DATEFIRST 1
SET NOCOUNT ON
GO
--Create ISO week Function (thanks BOL)
CREATE FUNCTION ISOweek ( #DATE DATETIME )
RETURNS INT
AS
BEGIN
DECLARE #ISOweek INT
SET #ISOweek = DATEPART(wk, #DATE) + 1 - DATEPART(wk, CAST(DATEPART(yy, #DATE) AS CHAR(4)) + '0104')
--Special cases: Jan 1-3 may belong to the previous year
IF ( #ISOweek = 0 )
SET #ISOweek = dbo.ISOweek(CAST(DATEPART(yy, #DATE) - 1 AS CHAR(4)) + '12' + CAST(24 + DATEPART(DAY, #DATE) AS CHAR(2))) + 1
--Special case: Dec 29-31 may belong to the next year
IF ( ( DATEPART(mm, #DATE) = 12 )
AND ( ( DATEPART(dd, #DATE) - DATEPART(dw, #DATE) ) >= 28 )
)
SET #ISOweek = 1
RETURN(#ISOweek)
END
GO
--END ISOweek
--CREATE Easter algorithm function
--Thanks to Rockmoose (http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=45689)
CREATE FUNCTION fnDLA_GetEasterdate ( #year INT )
RETURNS CHAR(8)
AS
BEGIN
-- Easter date algorithm of Delambre
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 ,
#O INT ,
#R INT
SET #A = #YEAR % 19
SET #B = #YEAR / 100
SET #C = #YEAR % 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
SET #O = 22 + #H + #L - 7 * #M
IF #O > 31
BEGIN
SET #R = #O - 31 + 400 + #YEAR * 10000
END
ELSE
BEGIN
SET #R = #O + 300 + #YEAR * 10000
END
RETURN #R
END
GO
--END fnDLA_GetEasterdate
--Create the table
CREATE TABLE MyDateTable
(
FullDate DATETIME NOT NULL
CONSTRAINT PK_FullDate PRIMARY KEY CLUSTERED ,
Period INT ,
ISOWeek INT ,
WorkingDay VARCHAR(1) CONSTRAINT DF_MyDateTable_WorkDay DEFAULT 'Y'
)
GO
--End table create
--Populate table with required dates
DECLARE #DateFrom DATETIME ,
#DateTo DATETIME ,
#Period INT
SET #DateFrom = CONVERT(DATETIME, '20000101')
--yyyymmdd (1st Jan 2000) amend as required
SET #DateTo = CONVERT(DATETIME, '20991231')
--yyyymmdd (31st Dec 2099) amend as required
WHILE #DateFrom <= #DateTo
BEGIN
SET #Period = CONVERT(INT, LEFT(CONVERT(VARCHAR(10), #DateFrom, 112), 6))
INSERT MyDateTable
( FullDate ,
Period ,
ISOWeek
)
SELECT #DateFrom ,
#Period ,
dbo.ISOweek(#DateFrom)
SET #DateFrom = DATEADD(dd, +1, #DateFrom)
END
GO
--End population
/* Start of WorkingDays UPDATE */
UPDATE MyDateTable
SET WorkingDay = 'B' --B = Bank Holiday
--------------------------------EASTER---------------------------------------------
WHERE FullDate = DATEADD(dd, -2, CONVERT(DATETIME, dbo.fnDLA_GetEasterdate(DATEPART(yy, FullDate)))) --Good Friday
OR FullDate = DATEADD(dd, +1, CONVERT(DATETIME, dbo.fnDLA_GetEasterdate(DATEPART(yy, FullDate))))
--Easter Monday
GO
UPDATE MyDateTable
SET WorkingDay = 'B'
--------------------------------NEW YEAR-------------------------------------------
WHERE FullDate IN ( SELECT MIN(FullDate)
FROM MyDateTable
WHERE DATEPART(mm, FullDate) = 1
AND DATEPART(dw, FullDate) NOT IN ( 6, 7 )
GROUP BY DATEPART(yy, FullDate) )
---------------------MAY BANK HOLIDAYS(Always Monday)------------------------------
OR FullDate IN ( SELECT MIN(FullDate)
FROM MyDateTable
WHERE DATEPART(mm, FullDate) = 5
AND DATEPART(dw, FullDate) = 1
GROUP BY DATEPART(yy, FullDate) )
OR FullDate IN ( SELECT MAX(FullDate)
FROM MyDateTable
WHERE DATEPART(mm, FullDate) = 5
AND DATEPART(dw, FullDate) = 1
GROUP BY DATEPART(yy, FullDate) )
--------------------AUGUST BANK HOLIDAY(Always Monday)------------------------------
OR FullDate IN ( SELECT MAX(FullDate)
FROM MyDateTable
WHERE DATEPART(mm, FullDate) = 8
AND DATEPART(dw, FullDate) = 1
GROUP BY DATEPART(yy, FullDate) )
--------------------XMAS(Move to next working day if on Sat/Sun)--------------------
OR FullDate IN ( SELECT CASE WHEN DATEPART(dw, FullDate) IN ( 6, 7 ) THEN DATEADD(dd, +2, FullDate)
ELSE FullDate
END
FROM MyDateTable
WHERE DATEPART(mm, FullDate) = 12
AND DATEPART(dd, FullDate) IN ( 25, 26 ) )
GO
---------------------------------------WEEKENDS--------------------------------------
UPDATE MyDateTable
SET WorkingDay = 'N'
WHERE DATEPART(dw, FullDate) IN ( 6, 7 )
GO
/* End of WorkingDays UPDATE */
--SELECT * FROM MyDateTable ORDER BY 1
DROP FUNCTION fnDLA_GetEasterdate
DROP FUNCTION ISOweek
--DROP TABLE MyDateTable
SET NOCOUNT OFF
Once you have created the table, finding the number of working days is easy peasy:
SELECT COUNT(FullDate) AS WorkingDays
FROM dbo.tbl_WorkingDays
WHERE WorkingDay = 'Y'
AND FullDate >= CONVERT(DATETIME, '10/01/2013', 103)
AND FullDate < CONVERT(DATETIME, '15/01/2013', 103)
Note that this script includes UK bank holidays, i'm not sure what region you're in.
Here's a simple function that counts working days not including Saturday and Sunday (when counting holidays isn't necessary):
CREATE FUNCTION dbo.udf_GetBusinessDays (
#START_DATE DATE,
#END_DATE DATE
)
RETURNS INT
WITH EXECUTE AS CALLER
AS
BEGIN
DECLARE #NUMBER_OF_DAYS INT = 0;
DECLARE #DAY_COUNTER INT = 0;
DECLARE #BUSINESS_DAYS INT = 0;
DECLARE #CURRENT_DATE DATE;
DECLARE #DAYNAME NVARCHAR(9)
SET #NUMBER_OF_DAYS = DATEDIFF(DAY, #START_DATE, #END_DATE);
WHILE #DAY_COUNTER <= #NUMBER_OF_DAYS
BEGIN
SET #CURRENT_DATE = DATEADD(DAY, #DAY_COUNTER, #START_DATE)
SET #DAYNAME = DATENAME(WEEKDAY, #CURRENT_DATE)
SET #DAY_COUNTER += 1
IF #DAYNAME = N'Saturday' OR #DAYNAME = N'Sunday'
BEGIN
CONTINUE
END
ELSE
BEGIN
SET #BUSINESS_DAYS += 1
END
END
RETURN #BUSINESS_DAYS
END
GO
This is the method I normally use (When not using a calendar table):
DECLARE #T TABLE (Date1 DATE, Date2 DATE);
INSERT #T VALUES ('20130110', '20130115'), ('20120101', '20130101'), ('20120611', '20120701');
SELECT Date1, Date2, WorkingDays
FROM #T t
CROSS APPLY
( SELECT [WorkingDays] = COUNT(*)
FROM Master..spt_values s
WHERE s.Number BETWEEN 1 AND DATEDIFF(DAY, t.date1, t.Date2)
AND s.[Type] = 'P'
AND DATENAME(WEEKDAY, DATEADD(DAY, s.number, t.Date1)) NOT IN ('Saturday', 'Sunday')
) wd
If like I do you have a table with holidays in you can add this in too:
SELECT Date1, Date2, WorkingDays
FROM #T t
CROSS APPLY
( SELECT [WorkingDays] = COUNT(*)
FROM Master..spt_values s
WHERE s.Number BETWEEN 1 AND DATEDIFF(DAY, t.date1, t.Date2)
AND s.[Type] = 'P'
AND DATENAME(WEEKDAY, DATEADD(DAY, s.number, t.Date1)) NOT IN ('Saturday', 'Sunday')
AND NOT EXISTS
( SELECT 1
FROM HolidayTable ht
WHERE ht.Date = DATEADD(DAY, s.number, t.Date1)
)
) wd
The above will only work if your dates are within 2047 days of each other, if you are likely to be calculating larger date ranges you can use this:
SELECT Date1, Date2, WorkingDays
FROM #T t
CROSS APPLY
( SELECT [WorkingDays] = COUNT(*)
FROM ( SELECT [Number] = ROW_NUMBER() OVER(ORDER BY s.number)
FROM Master..spt_values s
CROSS JOIN Master..spt_values s2
) s
WHERE s.Number BETWEEN 1 AND DATEDIFF(DAY, t.date1, t.Date2)
AND DATENAME(WEEKDAY, DATEADD(DAY, s.number, t.Date1)) NOT IN ('Saturday', 'Sunday')
) wd
I did my code in SQL SERVER 2008 (MS SQL) . It works fine for me. I hope it will help you.
DECLARE #COUNTS int,
#STARTDATE date,
#ENDDATE date
SET #STARTDATE ='01/21/2013' /*Start date in mm/dd/yyy */
SET #ENDDATE ='01/26/2013' /*End date in mm/dd/yyy */
SET #COUNTS=0
WHILE (#STARTDATE<=#ENDDATE)
BEGIN
/*Check for holidays*/
IF ( DATENAME(weekday,#STARTDATE)<>'Saturday' and DATENAME(weekday,#STARTDATE)<>'Sunday')
BEGIN
SET #COUNTS=#COUNTS+1
END
SET #STARTDATE=DATEADD(day,1,#STARTDATE)
END
/* Display the no of working days */
SELECT #COUNTS
By Combining #Aaron Bertrand's answer and the Easter Calculation from #HeavenCore's and adding some code of my own, this code creates a calendar from 2000 to 2049 that includes UK (England) Bank Holidays. Usage and notes as per Aaron's answer:
DECLARE #s DATE, #e DATE;
SELECT #s = '2000-01-01' , #e = '2049-12-31';
-- Insert statements for procedure here
CREATE TABLE dbo.Calendar
(
dt DATE PRIMARY KEY, -- use SMALLDATETIME if < SQL Server 2008
IsWorkDay BIT
);
INSERT dbo.Calendar(dt, IsWorkDay)
SELECT DATEADD(DAY, n-1, '2000-01-01'), 1
FROM
(
SELECT TOP (DATEDIFF(DAY, #s, #e)+1) ROW_NUMBER()
OVER (ORDER BY s1.[object_id])
FROM sys.all_objects AS s1
CROSS JOIN sys.all_objects AS s2
) AS x(n);
SET DATEFIRST 1;
-- weekends
UPDATE dbo.Calendar SET IsWorkDay = 0
WHERE DATEPART(WEEKDAY, dt) IN (6,7);
-- Christmas
UPDATE dbo.Calendar SET IsWorkDay = 0
WHERE IsWorkDay = 1 and MONTH(dt) = 12 and
(DAY(dt) in (25,26) or
(DAY(dt) in (27, 28) and DATEPART(WEEKDAY, dt) IN (1,2)) );
-- New Year
UPDATE dbo.Calendar SET IsWorkDay = 0
WHERE IsWorkDay = 1 and MONTH(dt) = 1 AND
( DAY(dt) = 1 or (DAY(dt) IN (2,3) AND DATEPART(WEEKDAY, dt)=1 ));
-- Easter
UPDATE dbo.Calendar SET IsWorkDay = 0
WHERE dt = DATEADD(dd, -2, CONVERT(DATETIME, dbo.fnDLA_GetEasterdate(DATEPART(yy, dt)))) --Good Friday
OR dt = DATEADD(dd, +1, CONVERT(DATETIME, dbo.fnDLA_GetEasterdate(DATEPART(yy, dt)))) --Easter Monday
-- May Day (first Monday in May)
UPDATE dbo.Calendar SET IsWorkDay = 0
WHERE MONTH(dt) = 5 AND DATEPART(WEEKDAY, dt)=1 and DAY(DT)<8;
-- Spring Bank Holiday (last Monday in May apart from 2022 when moved to include Platinum Jubilee bank holiday)
UPDATE dbo.Calendar SET IsWorkDay = 0
WHERE
(YEAR(dt)=2022 and MONTH(dt) = 6 AND DAY(dt) IN (2,3)) OR
(YEAR(dt)<>2022 and MONTH(dt) = 5 AND DATEPART(WEEKDAY, dt)=1 and DAY(DT)>24);
-- Summer Bank Holiday (last Monday in August)
UPDATE dbo.Calendar SET IsWorkDay = 0
WHERE MONTH(dt) = 8 AND DATEPART(WEEKDAY, dt)=1 and DAY(DT)>24;
I need to calculate the number of FULL month in SQL, i.e.
2009-04-16 to 2009-05-15 => 0 full month
2009-04-16 to 2009-05-16 => 1 full month
2009-04-16 to 2009-06-16 => 2 full months
I tried to use DATEDIFF, i.e.
SELECT DATEDIFF(MONTH, '2009-04-16', '2009-05-15')
but instead of giving me full months between the two date, it gives me the difference of the month part, i.e.
1
anyone know how to calculate the number of full months in SQL Server?
The original post had some bugs... so I re-wrote and packaged it as a UDF.
CREATE FUNCTION FullMonthsSeparation
(
#DateA DATETIME,
#DateB DATETIME
)
RETURNS INT
AS
BEGIN
DECLARE #Result INT
DECLARE #DateX DATETIME
DECLARE #DateY DATETIME
IF(#DateA < #DateB)
BEGIN
SET #DateX = #DateA
SET #DateY = #DateB
END
ELSE
BEGIN
SET #DateX = #DateB
SET #DateY = #DateA
END
SET #Result = (
SELECT
CASE
WHEN DATEPART(DAY, #DateX) > DATEPART(DAY, #DateY)
THEN DATEDIFF(MONTH, #DateX, #DateY) - 1
ELSE DATEDIFF(MONTH, #DateX, #DateY)
END
)
RETURN #Result
END
GO
SELECT dbo.FullMonthsSeparation('2009-04-16', '2009-05-15') as MonthSep -- =0
SELECT dbo.FullMonthsSeparation('2009-04-16', '2009-05-16') as MonthSep -- =1
SELECT dbo.FullMonthsSeparation('2009-04-16', '2009-06-16') as MonthSep -- =2
select case when DATEPART(D,End_dATE) >=DATEPART(D,sTAR_dATE)
THEN ( case when DATEPART(M,End_dATE) = DATEPART(M,sTAR_dATE) AND DATEPART(YYYY,End_dATE) = DATEPART(YYYY,sTAR_dATE)
THEN 0 ELSE DATEDIFF(M,sTAR_dATE,End_dATE)END )
ELSE DATEDIFF(M,sTAR_dATE,End_dATE)-1 END
What's your definition of a month? Technically a month can be 28,29,30 or 31 days depending on the month and leap years.
It seems you're considering a month to be 30 days since in your example you disregarded that May has 31 days, so why not just do the following?
SELECT DATEDIFF(DAY, '2009-04-16', '2009-05-15')/30
, DATEDIFF(DAY, '2009-04-16', '2009-05-16')/30
, DATEDIFF(DAY, '2009-04-16', '2009-06-16')/30
The dateadd function can be used to offset to the beginning of the month. If the endDate has a day part less than startDate, it will get pushed to the previous month, thus datediff will give the correct number of months.
DATEDIFF(MONTH, DATEADD(DAY,-DAY(startDate)+1,startDate),DATEADD(DAY,-DAY(startDate)+1,endDate))
This is for ORACLE only and not for SQL-Server:
months_between(to_date ('2009/05/15', 'yyyy/mm/dd'),
to_date ('2009/04/16', 'yyyy/mm/dd'))
And for full month:
round(months_between(to_date ('2009/05/15', 'yyyy/mm/dd'),
to_date ('2009/04/16', 'yyyy/mm/dd')))
Can be used in Oracle 8i and above.
I know this is an old question, but as long as the dates are >= 01-Jan-1753 I use:
DATEDIFF(MONTH, DATEADD(DAY,-DAY(#Start)+1,#Start),DATEADD(DAY,-DAY(#Start)+1,#End))
DATEDIFF() is designed to return the number boundaries crossed between the two dates for the span specified. To get it to do what you want, you need to make an additional adjustment to account for when the dates cross a boundary but don't complete the full span.
WITH
-- Count how many months must be added to #StartDate to exceed #DueDate
MONTHS_SINCE(n, [Month_hence], [IsFull], [RemainingDays] ) AS (
SELECT
1 as n,
DATEADD(Day, -1, DATEADD(Month, 1, #StartDate)) AS Month_hence
,CASE WHEN (DATEADD(Day, -1, DATEADD(Month, 1, #StartDate)) <= #LastDueDate)
THEN 1
ELSE 0
END AS [IsFull]
,DATEDIFF(day, #StartDate, #LastDueDate) as [RemainingDays]
UNION ALL
SELECT
n+1,
--DateAdd(Month, 1, Month_hence) as Month_hence -- No, causes propagation of short month discounted days
DATEADD(Day, -1, DATEADD(Month, n+1, #StartDate)) as Month_hence
,CASE WHEN (DATEADD(Day, -1, DATEADD(Month, n+1, #StartDate)) <= #LastDueDate)
THEN 1
ELSE 0
END AS [IsFull]
,DATEDIFF(day, DATEADD(Day, -1, DATEADD(Month, n, #StartDate)), #LastDueDate)
FROM MONTHS_SINCE
WHERE Month_hence<( #LastDueDate --WHERE Period= 1
)
), --SELECT * FROM MONTHS_SINCE
MONTH_TALLY (full_months_over_all_terms, months_over_all_terms, days_in_incomplete_month ) AS (
SELECT
COALESCE((SELECT MAX(n) FROM MONTHS_SINCE WHERE isFull = 1),1) as full_months_over_all_terms,
(SELECT MAX(n) FROM MONTHS_SINCE ) as months_over_all_terms,
COALESCE((SELECT [RemainingDays] FROM MONTHS_SINCE WHERE isFull = 0),0) as days_in_incomplete_month
) SELECT * FROM MONTH_TALLY;
Is not necesary to create the function only the #result part. For example:
Select Name,
(SELECT CASE WHEN
DATEPART(DAY, '2016-08-28') > DATEPART(DAY, '2016-09-29')
THEN DATEDIFF(MONTH, '2016-08-28', '2016-09-29') - 1
ELSE DATEDIFF(MONTH, '2016-08-28', '2016-09-29') END) as NumberOfMonths
FROM
tableExample;
This answer follows T-SQL format. I conceptualize this problem as one of a linear-time distance between two date points in datetime format, call them Time1 and Time2; Time1 should be aligned to the 'older in time' value you are dealing with (say a Birth date or a widget Creation date or a journey Start date) and Time2 should be aligned with the 'newer in time' value (say a snapshot date or a widget completion date or a journey checkpoint-reached date).
DECLARE #Time1 DATETIME
SET #Time1 = '12/14/2015'
DECLARE #Time2 DATETIME
SET #Time2 = '12/15/2016'
The solution leverages simple measurement, conversion and calculations of the serial intersections of multiple cycles of different lengths; here: Century,Decade,Year,Month,Day (Thanks Mayan Calendar for the concept!). A quick note of thanks: I thank other contributors to Stack Overflow for showing me some of the component functions in this process that I've stitched together. I've positively rated these in my time on this forum.
First, construct a horizon that is the linear set of the intersections of the Century,Decade,Year,Month cycles, incremental by month. Use the cross join Cartesian function for this. (Think of this as creating the cloth from which we will cut a length between two 'yyyy-mm' points in order to measure distance):
SELECT
Linear_YearMonths = (centuries.century + decades.decade + years.[year] + months.[Month]),
1 AS value
INTO #linear_months
FROM
(SELECT '18' [century] UNION ALL
SELECT '19' UNION ALL
SELECT '20') centuries
CROSS JOIN
(SELECT '0' [decade] UNION ALL
SELECT '1' UNION ALL
SELECT '2' UNION ALL
SELECT '3' UNION ALL
SELECT '4' UNION ALL
SELECT '5' UNION ALL
SELECT '6' UNION ALL
SELECT '7' UNION ALL
SELECT '8' UNION ALL
SELECT '9') decades
CROSS JOIN
(SELECT '1' [year] UNION ALL
SELECT '2' UNION ALL
SELECT '3' UNION ALL
SELECT '4' UNION ALL
SELECT '5' UNION ALL
SELECT '6' UNION ALL
SELECT '7' UNION ALL
SELECT '8' UNION ALL
SELECT '9' UNION ALL
SELECT '0') years
CROSS JOIN
(SELECT '-01' [month] UNION ALL
SELECT '-02' UNION ALL
SELECT '-03' UNION ALL
SELECT '-04' UNION ALL
SELECT '-05' UNION ALL
SELECT '-06' UNION ALL
SELECT '-07' UNION ALL
SELECT '-08' UNION ALL
SELECT '-09' UNION ALL
SELECT '-10' UNION ALL
SELECT '-11' UNION ALL
SELECT '-12') [months]
ORDER BY 1
Then, convert your Time1 and Time2 date points into the 'yyyy-mm' format (Think of these as the coordinate cut points on the whole cloth). Retain the original datetime versions of the points as well:
SELECT
Time1 = #Time1,
[YYYY-MM of Time1] = CASE
WHEN LEFT(MONTH(#Time1),1) <> '1' OR MONTH(#Time1) = '1'
THEN (CAST(YEAR(#Time1) AS VARCHAR) + '-' + '0' + CAST(MONTH(#Time1) AS VARCHAR))
ELSE (CAST(YEAR(#Time1) AS VARCHAR) + '-' + CAST(MONTH(#Time1) AS VARCHAR))
END,
Time2 = #Time2,
[YYYY-MM of Time2] = CASE
WHEN LEFT(MONTH(#Time2),1) <> '1' OR MONTH(#Time2) = '1'
THEN (CAST(YEAR(#Time2) AS VARCHAR) + '-' + '0' + CAST(MONTH(#Time2) AS VARCHAR))
ELSE (CAST(YEAR(#Time2) AS VARCHAR) + '-' + CAST(MONTH(#Time2) AS VARCHAR))
END
INTO #datepoints
Then, Select the ordinal distance of 'yyyy-mm' units, less one to convert to cardinal distance (i.e. cut a piece of cloth from the whole cloth at the identified cut points and get its raw measurement):
SELECT
d.*,
Months_Between = (SELECT (SUM(l.value) - 1) FROM #linear_months l
WHERE l.[Linear_YearMonths] BETWEEN d.[YYYY-MM of Time1] AND d.[YYYY-MM of Time2])
FROM #datepoints d
Raw Output:
I call this a 'raw distance' because the month component of the 'yyyy-mm' cardinal distance may be one too many; the day cycle components within the month need to be compared to see if this last month value should count. In this example specifically, the raw output distance is '12'. But this wrong as 12/14 is before 12/15, so therefore only 11 full months have lapsed--its just one day shy of lapsing through the 12th month. We therefore have to bring in the intra-month day cycle to get to a final answer. Insert a 'month,day' position comparison between the to determine if the latest date point month counts nominally, or not:
SELECT
d.*,
Months_Between = (SELECT (SUM(l.value) - 1) FROM AZ_VBP.[MY].[edg_Linear_YearMonths] l
WHERE l.[Linear_YearMonths] BETWEEN d.[YYYY-MM of Time1] AND d.[YYYY-MM of Time2])
+ (CASE WHEN DAY(Time1) < DAY(Time2)
THEN -1
ELSE 0
END)
FROM #datepoints d
Final Output:
The correct answer of '11' is now our output. And so, I hope this helps. Thanks!
select CAST(DATEDIFF(MONTH, StartDate, EndDate) AS float) -
(DATEPART(dd,StartDate) - 1.0) / DATEDIFF(DAY, StartDate, DATEADD(MONTH, 1, StartDate)) +
(DATEPART(dd,EndDate)*1.0 ) / DATEDIFF(DAY, EndDate, DATEADD(MONTH, 1, EndDate))
I realize this is an old post, but I created this interesting solution that I think is easy to implement using a CASE statement.
Estimate the difference using DATEDIFF, and then test the months before and after using DATEADD to find the best date. This assumes Jan 31 to Feb 28 is 1 month (because it is).
DECLARE #First date = '2015-08-31'
DECLARE #Last date = '2016-02-28'
SELECT
#First as [First],
#Last as [Last],
DateDiff(Month, #First, #Last) as [DateDiff Thinks],
CASE
WHEN DATEADD(Month, DATEDIFF(Month, #First, #Last) +1, #First) <= #Last Then DATEDIFF(Month, #First, #Last) +1
WHEN DATEADD(Month, DATEDIFF(Month, #First, #Last) , #First) <= #Last Then DATEDIFF(Month, #First, #Last)
WHEN DATEADD(Month, DATEDIFF(Month, #First, #Last) -1, #First) <= #Last Then DATEDIFF(Month, #First, #Last) -1
END as [Actual Months Apart]
SIMPLE AND EASY WAY, Just Copy and Paste this FULL code to MS SQL and Execute :
declare #StartDate date='2019-01-31'
declare #EndDate date='2019-02-28'
SELECT
DATEDIFF(MONTH, #StartDate, #EndDate)+
(
case
when format(#StartDate,'yyyy-MM') != format(#EndDate,'yyyy-MM') AND DATEPART(DAY,#StartDate) > DATEPART(DAY,#EndDate) AND DATEPART(DAY,#EndDate) = DATEPART(DAY,EOMONTH(#EndDate)) then 0
when format(#StartDate,'yyyy-MM') != format(#EndDate,'yyyy-MM') AND DATEPART(DAY,#StartDate) > DATEPART(DAY,#EndDate) then -1
else 0
end
)
as NumberOfMonths
All you need to do is deduct the additional month if the end date has not yet passed the day of the month in the start date.
DECLARE #StartDate AS DATE = '2019-07-17'
DECLARE #EndDate AS DATE = '2019-09-15'
DECLARE #MonthDiff AS INT = DATEDIFF(MONTH,#StartDate,#EndDate)
SELECT #MonthDiff -
CASE
WHEN FORMAT(#StartDate,'dd') > FORMAT(#EndDate,'dd') THEN 1
ELSE 0
END
You can create this function to calculate absolute difference between two dates.
As I found using DATEDIFF inbuilt system function we will get the difference only in months, days and years. For example : Let say there are two dates 18-Jan-2018 and 15-Jan-2019. So the difference between those dates will be given by DATEDIFF in month as 12 months where as it is actually 11 Months 28 Days. So using the function given below, we can find absolute difference between two dates.
CREATE FUNCTION GetDurationInMonthAndDays(#First_Date DateTime,#Second_Date DateTime)
RETURNS VARCHAR(500)
AS
BEGIN
DECLARE #RESULT VARCHAR(500)=''
DECLARE #MONTHS TABLE(MONTH_ID INT,MONTH_NAME VARCHAR(100),MONTH_DAYS INT)
INSERT INTO #MONTHS
SELECT 1,'Jan',31
union SELECT 2,'Feb',28
union SELECT 3,'Mar',31
union SELECT 4,'Apr',30
union SELECT 5,'May',31
union SELECT 6,'Jun',30
union SELECT 7,'Jul',31
union SELECT 8,'Aug',31
union SELECT 9,'Sep',30
union SELECT 10,'Oct',31
union SELECT 11,'Nov',30
union SELECT 12,'Jan',31
IF(#Second_Date>#First_Date)
BEGIN
declare #month int=0
declare #days int=0
declare #first_year int
declare #second_year int
SELECT #first_year=Year(#First_Date)
SELECT #second_year=Year(#Second_Date)+1
declare #first_month int
declare #second_month int
SELECT #first_month=Month(#First_Date)
SELECT #second_month=Month(#Second_Date)
if(#first_month=2)
begin
IF((#first_year%100<>0) AND (#first_year%4=0) OR (#first_year%400=0))
BEGIN
SELECT #days=29-day(#First_Date)
END
else
begin
SELECT #days=28-day(#First_Date)
end
end
else
begin
SELECT #days=(SELECT MONTH_DAYS FROM #MONTHS WHERE MONTH_ID=#first_month)-day(#First_Date)
end
SELECT #first_month=#first_month+1
WHILE #first_year<#second_year
BEGIN
if(#first_month=13)
begin
set #first_month=1
end
WHILE #first_month<13
BEGIN
if(#first_year=Year(#Second_Date))
begin
if(#first_month=#second_month)
begin
SELECT #days=#days+DAY(#Second_Date)
break;
end
else
begin
SELECT #month=#month+1
end
end
ELSE
BEGIN
SELECT #month=#month+1
END
SET #first_month=#first_month+1
END
SET #first_year = #first_year + 1
END
select #month=#month+(#days/30)
select #days=#days%30
if(#days>0)
begin
SELECT #RESULT=CAST(#month AS VARCHAR)+' Month '+CAST(#days AS VARCHAR)+' Days '
end
else
begin
SELECT #RESULT=CAST(#month AS VARCHAR)+' Month '
end
END
ELSE
BEGIN
SELECT #RESULT='ERROR'
END
RETURN #RESULT
END
SELECT dateadd(dd,number,DATEADD(yy, DATEDIFF(yy,0,getdate()), 0)) AS gun FROM master..spt_values
WHERE type = 'p'
AND year(dateadd(dd,number,DATEADD(yy, DATEDIFF(yy,0,getdate()), 0)))=year(DATEADD(yy, DATEDIFF(yy,0,getdate()), 0))
CREATE FUNCTION ufFullMonthDif (#dStart DATE, #dEnd DATE)
RETURNS INT
AS
BEGIN
DECLARE #dif INT,
#dEnd2 DATE
SET #dif = DATEDIFF(MONTH, #dStart, #dEnd)
SET #dEnd2 = DATEADD (MONTH, #dif, #dStart)
IF #dEnd2 > #dEnd
SET #dif = #dif - 1
RETURN #dif
END
GO
SELECT dbo.ufFullMonthDif ('2009-04-30', '2009-05-01')
SELECT dbo.ufFullMonthDif ('2009-04-30', '2009-05-29')
SELECT dbo.ufFullMonthDif ('2009-04-30', '2009-05-30')
SELECT dbo.ufFullMonthDif ('2009-04-16', '2009-05-15')
SELECT dbo.ufFullMonthDif ('2009-04-16', '2009-05-16')
SELECT dbo.ufFullMonthDif ('2009-04-16', '2009-06-16')
SELECT dbo.ufFullMonthDif ('2019-01-31', '2019-02-28')
Making Some changes to the Above function worked for me.
CREATE FUNCTION [dbo].[FullMonthsSeparation]
(
#DateA DATETIME,
#DateB DATETIME
)
RETURNS INT
AS
BEGIN
DECLARE #Result INT
DECLARE #DateX DATETIME
DECLARE #DateY DATETIME
IF(#DateA < #DateB)
BEGIN
SET #DateX = #DateA
SET #DateY = #DateB
END
ELSE
BEGIN
SET #DateX = #DateB
SET #DateY = #DateA
END
SET #Result = (
SELECT
CASE
WHEN DATEPART(DAY, #DateX) > DATEPART(DAY, #DateY)
THEN DATEDIFF(MONTH, #DateX, #DateY) - iif(EOMONTH(#DateY) = #DateY, 0, 1)
ELSE DATEDIFF(MONTH, #DateX, #DateY)
END
)
RETURN #Result
END
Declare #FromDate datetime, #ToDate datetime,
#TotalMonth int ='2021-10-01', #TotalDay='2021-12-31' int,
#Month int = 0
WHILE #ToDate > DATEADD(MONTH,#Month,#FromDate)
BEGIN
SET #Month = #Month +1
END
SET #TotalMonth = #Month -1
SET #TotalDay = DATEDIFF(DAY, DATEADD(MONTH,#TotalMonth, #FromDate),#ToDate) +1
IF(#TotalDay = DAY(EOMONTH(#ToDate)))
BEGIN
SET #TotalMonth = #TotalMonth +1
SET #TotalDay =0
END
Result #TotalMonth = 3, #TotalDay=0
if you are using PostGres only --
SELECT (DATE_PART('year', '2012-01-01'::date) - DATE_PART('year', '2011-10-02'::date)) * 12 +
(DATE_PART('month', '2012-01-01'::date) - DATE_PART('month', '2011-10-02'::date));
There are a lot of answers here that did not satisfy all the corner cases so I set about to fix them. This handles:
01/05/2021 - 02/04/2021 = 0 months
01/31/2021 - 02/28/2021 = 1 months
09/01/2021 - 10/31/2021 = 2 months
I think this generally handles all the cases needed.
declare #dateX date = '01/1/2022'
declare #datey date = '02/28/2022'
-- select datediff(month, #dateX, #datey) --Here for comparison
SELECT
CASE
WHEN DATEPART(DAY, #DateX) = 1 and DATEPART(DAY, #DateY) = DATEPART(DAY, eomonth(#DateY))
THEN DATEDIFF(MONTH, #DateX, #DateY) + 1
WHEN DATEPART(DAY, #DateX) > DATEPART(DAY, #DateY) and DATEPART(DAY, #DateY) != DATEPART(DAY, eomonth(#DateY))
THEN DATEDIFF(MONTH, #DateX, #DateY) - 1
ELSE DATEDIFF(MONTH, #DateX, #DateY)
END
I believe it is important to note that the question specifically asks for "full months between" AND that in the examples given each date is treated as "the START point of that date". This latter item is important because some comments state that year-01-31 to year-02-28 is a result of zero. This is correct. 1 complete day in January, plus 27 complete days in February (02-28 is the start of that day, so incomplete) is zero "full" months.
With that in mind I believe the following would meet the requirements IF StartDate is <= EndDate
(DATEPART(YEAR, EndDate) - DATEPART(YEAR, StartDate)) * 12
+ (DATEPART(MONTH, EndDate) - DATEPART(MONTH, StartDate))
- CASE WHEN DATEPART(DAY,EndDate) < DATEPART(DAY,StartDate) THEN 1 ELSE 0 END
To accommodate the possibility that the dates may be in any order then:
, CASE WHEN StartDate <= EndDate THEN
(DATEPART(YEAR, EndDate) - DATEPART(YEAR, StartDate)) * 12
+ (DATEPART(MONTH, EndDate) - DATEPART(MONTH, StartDate))
- CASE WHEN DATEPART(DAY,EndDate) < DATEPART(DAY,StartDate) THEN 1 ELSE 0 END
ELSE
(DATEPART(YEAR, StartDate) - DATEPART(YEAR, EndDate)) * 12
+ (DATEPART(MONTH, StartDate) - DATEPART(MONTH, EndDate))
- CASE WHEN DATEPART(DAY,StartDate) < DATEPART(DAY,EndDate) THEN 1 ELSE 0 END
END AS FullMnthsBtwn
For this sample:
select
StartDate, EndDate
into mytable
from (
values
(cast(getdate() as date),cast(getdate() as date)) -- both same date
-- original
,('2009-04-16','2009-05-15') -- > 0 full month
,('2009-04-16','2009-05-16') -- > 1 full month
,('2009-04-16','2009-06-16') -- > 2 full months
-- '1/31/2018' and endDate of '3/1/2018', I get a 0 – Eugene
, ('2018-01-31','2018-03-01')
-- some extras mentioned in comments, both of these should return 0 (in my opinion)
,('2009-01-31','2009-02-28')
,('2012-12-31','2013-02-28')
,('2022-05-15','2022-04-16') -- > 0 full month
,('2022-05-16','2022-04-16') -- > 1 full month
,('2021-06-16','2022-04-16') -- > 10 full months
) d (StartDate, EndDate)
query
select
StartDate
, EndDate
, CASE WHEN StartDate <= EndDate THEN
(DATEPART(YEAR, EndDate) - DATEPART(YEAR, StartDate)) * 12
+ (DATEPART(MONTH, EndDate) - DATEPART(MONTH, StartDate))
- CASE WHEN DATEPART(DAY,EndDate) < DATEPART(DAY,StartDate) THEN 1 ELSE 0 END
ELSE
(DATEPART(YEAR, StartDate) - DATEPART(YEAR, EndDate)) * 12
+ (DATEPART(MONTH, StartDate) - DATEPART(MONTH, EndDate))
- CASE WHEN DATEPART(DAY,StartDate) < DATEPART(DAY,EndDate) THEN 1 ELSE 0 END
END AS FullMnthsBtwn
from mytable
order by 1
result
+------------+------------+---------------+
| StartDate | EndDate | FullMnthsBtwn |
+------------+------------+---------------+
| 2009-01-31 | 2009-02-28 | 0 |
| 2009-04-16 | 2009-05-15 | 0 |
| 2009-04-16 | 2009-05-16 | 1 |
| 2009-04-16 | 2009-06-16 | 2 |
| 2012-12-31 | 2013-02-28 | 1 |
| 2018-01-31 | 2018-03-01 | 1 |
| 2021-06-16 | 2022-04-16 | 10 |
| 2022-05-15 | 2022-04-16 | 0 |
| 2022-05-16 | 2022-04-16 | 1 |
| 2022-07-09 | 2022-07-09 | 0 |
+------------+------------+---------------+
See db<>fiddle here (compares some other responses as well)
I got some ideas from the other answers, but none of them gave me exactly what I wanted.
The problem boils down to what I perceive a "month between" to be, which may be what others are also looking for also.
For example 25th February to 25th March would be one month to me, even though it is only 28 days. I would also consider 25th March to 25th April as one month at 31 days.
Also, I would consider 31st January to 2nd March as 1 month and 2 days even though it is 30 days between.
Also, fractions of a month are a bit meaningless as it depends on the length of a month and which month in the range do you choose to take a fraction of.
So, with that in mind, I came up with this function. It returns a decimal, the integer part is the number of months and the decimal part is the number of days, so a return value of 3.07 would mean 3 months and 7 days.
CREATE FUNCTION MonthsAndDaysBetween (#fromDt date, #toDt date)
RETURNS decimal(10,2)
AS
BEGIN
DECLARE #d1 date, #d2 date, #numM int, #numD int, #trc varchar(10);
IF(#fromDt < #toDt)
BEGIN
SET #d1 = #fromDt;
SET #d2 = #toDt;
END
ELSE
BEGIN
SET #d1 = #toDt;
SET #d2 = #fromDt;
END
IF DAY(#d1)>DAY(#d2)
SET #numM = year(#d2)*12+month(#d2)-year(#d1)*12-month(#d1)-1;
ELSE
SET #numM = year(#d2)*12+month(#d2)-year(#d1)*12-month(#d1);
IF YEAR(#d1) < YEAR(#d2) OR (YEAR(#d1) = YEAR(#d2) AND MONTH(#d1) < MONTH(#d2))
BEGIN
IF DAY(#d2) < DAY(#d1)
SET #numD = DAY(#d2) + DAY(EOMONTH(DATEADD(month,-1,#d2))) - DAY(#d1);
ELSE
SET #numD = DAY(#d2)-DAY(#d1);
END
ELSE
SET #numD = DAY(#d2)-DAY(#d1);
RETURN #numM + ABS(#numD) / 100.0;
END
In sql server, this formula works for going backward and forward in time.
DATEDIFF(month,#startdate, #enddate) + iif(#startdate <=#enddate,IIF(DAY(#startdate) > DAY(#enddate),-1,0),IIF(DAY(#startdate) < DAY(#enddate),+1, 0)))
SELECT 12 * (YEAR(end_date) - YEAR(start_date)) +
((MONTH(end_date) - MONTH(start_date))) +
SIGN(DAY(end_date) / DAY(start_date));
This works fine for me on SQL SERVER 2000.
Try:
trunc(Months_Between(date2, date1))
UPDATED
Right now, I just use
SELECT DATEDIFF(MONTH, '2019-01-31', '2019-02-28')
and SQL server returns the exact result (1).
I googled over internet.
And suggestion I found is to add +1 to the end.
Try do it like this:
Declare #Start DateTime
Declare #End DateTime
Set #Start = '11/1/07'
Set #End = '2/29/08'
Select DateDiff(Month, #Start, #End + 1)