Calculate Age from Date Of Birth using SQL Server

Here’s a query to calculate the Age in Years, Months, Days, Hours and Minutes

declare @birth_day datetime
set @birth_day ='19660527 12:34:22'
select
 years,
 months,
 case
 when day(@birth_day)>day(getdate())
 then day(getdate())+
 datediff(day,@birth_day,dateadd(month,datediff(month,0,@birth_day)+1,0))-1
 else day(getdate())-day(@birth_day)
 end as days,
 datepart(hour,convert(varchar(10),dateadd(minute,minutes,0),108)) as hours,
 datepart(minute,convert(varchar(10),dateadd(minute,minutes,0),108)) as minutes
from
(
select
 years,
 datediff(month,dateadd(year,years,@birth_day),getdate())+
 case
 when day(getdate())>=day(@birth_day)
 then 0
 else -1 
 end as months,
 datediff(minute,convert(varchar(8),@birth_day,108),
 convert(varchar(8),getdate(),108)) as minutes
from
(
select
 datediff(year,@birth_day,getdate()) +
 case
 when month(getdate())>=month(@birth_day)
 then 0
 else -1
 end as years
) as t
) as t

In the query shown above, the inner query finds the year difference between current date and birth date. The case expression checks whether current month is greater than the month of birth date. If it is greater, a full year is completed, else the full year is not completed and one year is reduced from the result.

A similar check is done for month too. The outer parts calculate the hours and minutes.

OUTPUT