How to calculate age from date of birth in sql

Hi ,

try this code block

  DECLARE @date datetime, @tmpdate datetime, @years int, @months int, @days int
SELECT @date = '2/29/04'

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 @years, @months, @days

Kelly's answer is almost correct. Very old thread, but this could help someone.

You can do this:

select datediff(year,[bd], getdate()) - case when month([bd]) > month(getdate()) or (month([bd]) = month(getdate()) and day([bd]) > day(getdate())) then 1 else 0 end age from [table]

Where table is your table name, and bd is the birth date field name in that table.

First you get the number of years from the birth date up to now.

datediff(year,[bd], getdate())

Then you need to check if the person already had this year's birthday, and if not, you need to subtract 1 from the total.

If the month is in the future

month([bd]) > month(getdate())

or if it is the birthday month but the day is in the future

(month([bd]) = month(getdate()) and day([bd]) > day(getdate()))

This is my solution for RAP, Report Object Pascal, as in ReportBuilder for Medisoft Report Professional

procedure AgeOnCalc(var Value: Variant);

var currentyear, currentmonth, currentday : integer;
    patientyear, patientmonth, patientday : integer;

begin

  decodedate(CurrentDate, currentyear, currentmonth, currentday);
  decodedate(Patient['Date of Birth'], patientyear, patientmonth, patientday);
  if (patientmonth > currentmonth) or ((patientmonth = currentmonth) and (patientday > currentday)) then
    value := currentyear - patientyear - 1
  else
    value := currentyear - patientyear;

end;

To calculate the average age today, you could use SELECT DATEDIFF(DAY, @Birth, GetDate()) / 365.25.

However, the calculation could get more complex if you want the exact age in days or years.

Select ID,
convert(Float,convert(int,convert(varchar(10),GETDATE(),112))) as Todayday,
convert(float,convert(int,convert(varchar(10),convert(date,ltrim(rtrim(DOB)))),112))) as DOB,
(convert(Float,convert(int,convert(varchar(10),GETDATE(),112))) -
convert(float,convert(int,convert(varchar(10),convert(date,ltrim(rtrim(DOB)))),112))))/10000 as AgeFloat,
Convert(int,(convert(Float,convert(int,convert(varchar(10),GETDATE(),112))) -
convert(float,convert(int,convert(varchar(10),convert(date,ltrim(rtrim(DOB)))),112))))/10000) as Age
From DOBTable

Notes:
Format todays date and birthdate as YYYYMMDD and subtract today-DOB.
Convert that number to float and divide by 10000.
The integer of that result is age.
Convert from Float to integer does not round the number.
Age is exact every time.
I have added steps to show these conversions, but you only need the Age line.
Convert(int,(convert(Float,convert(int,convert(varchar(10),GETDATE(),112))) -
convert(float,convert(int,convert(varchar(10),convert(date,ltrim(rtrim(DOB)))),112))))/10000) as Age

Here's another way using SQL that will get you their specific age based on the current date and their date of birth.

Below is written for Oracle.

select dob,
case when to_char(cast(sysdate as date),'mm') || to_char(cast(sysdate as date),'dd') >=
to_char(dob,'mm') || to_char(dob,'dd')
then to_char(cast(sysdate as date),'yyyy') - to_char(dob,'yyyy')
else to_char(cast(sysdate as date),'yyyy') - to_char(dob,'yyyy') - 1
end age
from my_table

Here is a version of the same sql that works for Netezza.

select dob,
case when lpad(extract (months from current_date),2,'0') ||
lpad(extract (days from current_date),2,'0') >=
lpad(extract (months from dob),2,'0') ||
lpad(extract (days from dob),2,'0')
then extract (years from current_date) - extract (years from dob)
else extract (years from current_date) - extract (years from dob) - 1
end age
from my_table


For SQL Server :

select dob,
case when right('00' + cast(month(getdate()) as varchar(2)),2) + right('00' + cast(day(getdate()) as varchar(2)),2) >=
right('00' + cast(month(dob) as varchar(2)),2) + right('00' + cast(day(dob) as varchar(2)),2)
then year(getdate()) - year(dob)
else year(getdate()) - year(dob) - 1
end age
from my_table

I know this is an older thread, but it will continue to be prevalent for years to come. To put everyone's minds at rest, I have tested a couple of the formulas presented on this thread to calculate age in years and both seem to be in sync. I personally I am leaning toward the first formula as it is short and elegant. If you want to put your mind at rest check it out for yourself:

/*Create table to hold every single DOB since 1/1/1900*/
Create table dbo.Temp(DOB Date)
go

/*populate table with age*/

;with temp as(
  select convert(date, '01/01/1900') As DOB
  Union all
  Select DateAdd(Day, 1, DOB)
  from temp
  Where DateAdd(Day, 1, DOB) <= Convert(Date, GetDate())
  )
Insert into dbo.Temp(DOB)
select DOB
from temp
option(maxrecursion 0)

/*test two formulas for calculating age*/

;with test as(
Select DOB, Age1 = FLOOR(DATEDIFF(DAY, DOB , getdate()) / 365.25),
  Age2 =
	case when right('00' + cast(month(getdate()) as varchar(2)),2) + right('00' + cast(day(getdate()) as varchar(2)),2) >= 
	right('00' + cast(month(dob) as varchar(2)),2) + right('00' + cast(day(DOB) as varchar(2)),2) 
	then year(getdate()) - year(DOB)
	else year(getdate()) - year(DOB) - 1 
	end
From dbo.Temp
)
select *
from test
where age1 <> age2

I know this question is old but I have an Inline Table Valued Function that calculates the age quite well.

The way it works is to calculate the difference between the @StartTime and @EndTime in months. Then it checks the day of @StartTime to see if it is greater than the day of @EndTime, if it is then subtract 1 from the month calculation because the person's birthday has not arrived yet. Otherwise, subtract 0.

By writing this as an Inline Table Valued Function rather than a Scalar function the query that it is used in will run very fast.

You can call it for a single calculation by:

SELECT AgeInYears FROM dbo.CalculateAgeInYears('1980-07-01', GETDATE())

Or you can use CROSS APPLY to calculate from a table:

SELECT *
FROM #SampleData AS t
CROSS APPLY dbo.CalculateAgeInYears(t.DOB, GETDATE()) AS fn

CREATE FUNCTION [dbo].[CalculateAgeInYears]
(	 	 
  @StartDate DATETIME,
  @EndDATE DATETIME
)	 	 
RETURNS TABLE	 	 
AS	 	 
RETURN	 	 
(
  SELECT (DATEDIFF(MONTH, @StartDate, @EndDate) - CASE WHEN DATEPART(DAY, @StartDate) > DATEPART(DAY, @EndDate) THEN 1 ELSE 0 END) / 12 AS AgeInYears
)

Similar to Solution 5 but avoids conversions back and forth from text to numeric.

Assumes date of birth (dob) and 'as of' date (as_of_date) are in date format.

floor((datepart (yy,as_of_date)+(datepart(mm,as_of_date)*.01)+(datepart(dd,as_of_date)*.0001))-(datepart (yy,dob)+(datepart(mm,dob)*.01)+(datepart(dd,dob)*.0001)))

For dob = 7/12/1960 and as_of_date = 3/12/2020:

2020.0312 - 1960.0712 = 59.9600

The decimal portion is gibberish, but you are only looking for the floor() portion, which is 59.

CREATE OR ALTER PROC AGE ( @dob datetime )
AS
DECLARE @year int ,@month INT,@day INT, @processyear datetime = @dob
select @year = datediff(yy,@processyear,GETDATE()) -
case
when (month(@DOB)>month(GETDATe())) OR MONTH(@DOB) = MONTH(GETDATE())AND DAY(@DOB)>DAY(GETDATE()) THEN 1 ELSE 0
END
SELECT @processyear = DATEADD(YEAR,@year,@processyear)

SELECT @MONTH = DATEDIFF(MONTH,@processyear,GETDATE()) -
case
when day(@DOB)>day(GETDATE())
then 1 else 0
end
PRINT @MONTH
select @processyear = DATEADD(month,@month,@processyear)

select @day =datediff(day,@processyear,getdate())
declare @age nvarchar(50)
set @age = cast(@year as nvarchar(4))+ 'years'+cast(@month as nvarchar(4)) + 'months' +cast(@day as nvarchar(4))+'days old'
SELECT @AGE

DECLARE @CurrentDate DATE = CAST(GETDATE() AS DATE), @DOB DATE = '1967-01-10', @Years INT = 0, @Months INT = 0, @Days INT = 0
SET @Years = DATEDIFF(DAY,@DOB,@CurrentDate)/365
SET @Months = DATEDIFF(MONTH,DATEADD(YEAR,DATEDIFF(DAY,@DOB,@CurrentDate)/365,@DOB),@CurrentDate)
SET @Days = DATEDIFF(DAY,DATEADD(Month,DATEDIFF(MONTH,DATEADD(YEAR,DATEDIFF(DAY,@DOB,@CurrentDate)/365,@DOB),@CurrentDate),DATEADD(YEAR,DATEDIFF(DAY,@DOB,@CurrentDate)/365,@DOB)),@CurrentDate)
SELECT CONCAT (@Years, ' Years, ', @Months, ' Months and ', @Days, ' Days') AS DateOfBirth

This give us exact Years, Months and Days. And we can create function out of this.