Get date difference in year, month, and days SQL - sql

Question

Is there a way to calculate how old someone is based on today's date and their birthday then display it in following manners:
If a user is less than (<) 1 year old THEN show their age in MM & days.
Example: 10 months & 2 days old
If a user is more than 1 year old AND less than 6 years old THEN show their age in YY & MM & days.
Example: 5 years & 3 months & 10 days old
If a user is more than 6 years old THEN display their age in YY.
Example: 12 years

Answer 1

This is basically what you are looking for:
DECLARE #date1 DATETIME
, #date2 DATETIME;
SELECT #date1 = '1/1/2008'
, #date2 = GETDATE();
SELECT CASE
WHEN DATEDIFF(YEAR, #date1, #date2) < 1 THEN CAST(DATEDIFF(mm, #date1, #date2) AS VARCHAR)+' Months & '+CAST(DATEDIFF(dd, DATEADD(mm, DATEDIFF(mm, #date1, #date2), #date1), #date2) AS VARCHAR)+' Days'
WHEN DATEDIFF(YEAR, #date1, #date2) BETWEEN 1 AND 5 THEN CAST(DATEDIFF(mm, #date1, #date2) / 12 AS VARCHAR)+' Years & '+CAST(DATEDIFF(mm, #date1, #date2) % 12 AS VARCHAR)+' Months'
WHEN DATEDIFF(YEAR, #date1, #date2) >= 6 THEN CAST(DATEDIFF(YEAR, #date1, #date2) AS VARCHAR)+' Years'
END;
Result for when a user is less than (<) 1 year old THEN show their age in MM & days:
Result for when a user is more than 1 year old AND less than 6 years old THEN show their age in YY & MM & days:
Result for when a user is more than 6 years old THEN display their age in YY:

Answer 2

from this previous question
How to calculate age in T-SQL with years, months, and days
you can do procedure like this
CREATE procedure [dbo].[proc_datediff]
(
#date datetime
)
as
begin
DECLARE #diff varchar(70)
DECLARE #tmpdate datetime, #years int, #months int, #days int
SELECT #tmpdate = #date
SELECT #years = DATEDIFF(yy, #tmpdate, GETDATE()) - CASE WHEN
(MONTH(#date) > MONTH(GETDATE())) OR (MONTH(#date) =
MONTH(GETDATE()) AND DAY(#date) > DAY(GETDATE())) THEN 1 ELSE 0 END
SELECT #tmpdate = DATEADD(yy, #years, #tmpdate)
SELECT #months = DATEDIFF(m, #tmpdate, GETDATE()) - CASE WHEN
DAY(#date) > DAY(GETDATE()) THEN 1 ELSE 0 END
SELECT #tmpdate = DATEADD(m, #months, #tmpdate)
SELECT #days = DATEDIFF(d, #tmpdate, GETDATE())
select #diff=
case
when #years < 1 then
concat( #months,' Months ',#days,' days ' )
when #years >=1 and #years < 6
then
concat(#years,' year ', #months,' Months ',#days,' days ' )
when #years >= 6 then
concat( #years,' years ' )
end;
select #diff
end
execute proc_datediff '1/1/2016'
go

Answer 3

CREATE FUNCTION [dbo].[FindDateDiff](#Date1 date,#Date2 date, #IncludeTheEnDate bit)
RETURNS TABLE
AS
RETURN
(
SELECT
CALC.Years,CALC.Months,D.Days,
Duration = RTRIM(Case When CALC.Years > 0 Then CONCAT(CALC.Years, ' year(s) ') Else '' End
+ Case When CALC.Months > 0 Then CONCAT(CALC.Months, ' month(s) ') Else '' End
+ Case When D.Days > 0 OR (CALC.Years=0 AND CALC.Months=0) Then CONCAT(D.Days, ' day(s)') Else '' End)
FROM (VALUES(IIF(#Date1<#Date2,#Date1,#Date2),DATEADD(DAY, IIF(#IncludeTheEnDate=0,0,1), IIF(#Date1<#Date2,#Date2,#Date1)))) T(StartDate, EndDate)
CROSS APPLY(Select
TempEndYear = Case When ISDATE(CONCAT(YEAR(T.EndDate), FORMAT(T.StartDate,'-MM-dd')))=1 Then CONCAT(YEAR(T.EndDate), FORMAT(T.StartDate,'-MM-dd'))
Else CONCAT(YEAR(T.EndDate),'-02-28') End
) TEY
CROSS APPLY(Select EndYear = Case When TEY.TempEndYear > T.EndDate Then DATEADD(YEAR, -1, TEY.TempEndYear) Else TEY.TempEndYear End) EY
CROSS APPLY(Select
Years = DATEDIFF(YEAR,T.StartDate,EY.EndYear),
Months = DATEDIFF(MONTH,EY.EndYear,T.EndDate)-IIF(DAY(EY.EndYear)>DAY(T.EndDate),1,0)
) CALC
CROSS APPLY(Select Days = DATEDIFF(DAY,DATEADD(MONTH,CALC.Months,DATEADD(YEAR,CALC.Years,T.StartDate)),T.EndDate)) D
)
Sample:
Select [From] = '2021-01-01',[To] = '2021-12-31',IncludeEndDate='Yes',* From dbo.FindDateDiff('2021-01-01','2021-12-31',1)
Select [From] = '2021-01-01',[To] = '2021-12-31',IncludeEndDate='No',* From dbo.FindDateDiff('2021-01-01','2021-12-31',0)
Select [From] = '2015-12-15',[To] = '2018-12-14',IncludeEndDate='Yes',* From dbo.FindDateDiff('2015-12-15','2018-12-14',1)
Select [From] = '2015-12-15',[To] = '2018-12-14',IncludeEndDate='No',* From dbo.FindDateDiff('2015-12-15','2018-12-14',0)

Answer 4

Probably not the most efficient way to go about it, but here's how I did it:
I had to first get the date difference between today's date and person's birthdate. I used it to get years, months, days, etc by combining it with ABS(), and Remainder (%) function.
declare #year int = 365
declare #month int = 30
declare #sixYears int = 2190
select
--CAST(DATEDIFF(mm, a.BirthDateTime, getdate()) AS VARCHAR) as GetMonth,
--CAST(DATEDIFF(dd, DATEADD(mm, DATEDIFF(mm, a.BirthDateTime, getdate()), a.BirthDateTime), getdate()) AS VARCHAR) as GetDays,
CASE
WHEN
DATEDIFF(dd,a.BirthDateTime,getdate()) < #year
THEN
cast((DATEDIFF(dd,a.BirthDateTime,getdate()) / (#month)) as varchar) +' Months & ' +
CAST(ABS(DATEDIFF(dd, DATEADD(mm, DATEDIFF(mm, a.BirthDateTime, getdate()), a.BirthDateTime), getdate())) AS VARCHAR)
+ ' Days'
WHEN
DATEDIFF(dd,a.BirthDateTime,getdate()) between #year and #sixYears
THEN
cast((DATEDIFF(dd,a.BirthDateTime,getdate()) / (#year)) as varchar) +' Years & ' +
CAST((DATEDIFF(mm, a.BirthDateTime, getdate()) % (12)) AS VARCHAR) + ' Months'
WHEN DATEDIFF(dd,a.BirthDateTime,getdate()) > #sixYears
THEN cast(a.Age as varchar) + ' Years'
end as FinalAGE,

Answer 5

dc.DayMarker = cast(getdate() as date)
DAYmarker is your date field.