题
什么是最好的方式来计算某人的年龄在年、月、日在T-SQL(SQL Server2000)?
的 datediff
功能不处理年的边界以及,加上越来越数月和数天,独立将是一个负担。我知道我可以做它在客户面相对容易,但我想做在我的 存储程序.
解决方案
这里是一些T-SQL给你的数量的年、月、日子,因为一天中指定@日期。它考虑到一个事实,DATEDIFF()计算差值而没有考虑什么样的一个月或一天,它是(所月份之间的差异8/31和9/1的1个月)和处理这一情况的声明,递减的结果在适当情况下。
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
其他提示
试试这个...
SELECT CASE WHEN
(DATEADD(year,DATEDIFF(year, @datestart ,@dateend) , @datestart) > @dateend)
THEN DATEDIFF(year, @datestart ,@dateend) -1
ELSE DATEDIFF(year, @datestart ,@dateend)
END
基本上"DateDiff(年...",给你的年龄的人将会把这一年,因此我刚才添加的情况下发言说,如果他们没有生日但这一年,然后减去1年,其他返回的价值。
简单的方法来获得的年龄作为案文如下:
Select cast((DATEDIFF(m, date_of_birth, GETDATE())/12) as varchar) + ' Y & ' +
cast((DATEDIFF(m, date_of_birth, GETDATE())%12) as varchar) + ' M' as Age
结果的格式将是:
**63 Y & 2 M**
实施算ISO格式的日期。
declare @now date,@dob date, @now_i int,@dob_i int, @days_in_birth_month int
declare @years int, @months int, @days int
set @now = '2013-02-28'
set @dob = '2012-02-29' -- Date of Birth
set @now_i = convert(varchar(8),@now,112) -- iso formatted: 20130228
set @dob_i = convert(varchar(8),@dob,112) -- iso formatted: 20120229
set @years = ( @now_i - @dob_i)/10000
-- (20130228 - 20120229)/10000 = 0 years
set @months =(1200 + (month(@now)- month(@dob))*100 + day(@now) - day(@dob))/100 %12
-- (1200 + 0228 - 0229)/100 % 12 = 11 months
set @days_in_birth_month = day(dateadd(d,-1,left(convert(varchar(8),dateadd(m,1,@dob),112),6)+'01'))
set @days = (sign(day(@now) - day(@dob))+1)/2 * (day(@now) - day(@dob))
+ (sign(day(@dob) - day(@now))+1)/2 * (@days_in_birth_month - day(@dob) + day(@now))
-- ( (-1+1)/2*(28 - 29) + (1+1)/2*(29 - 29 + 28))
-- Explain: if the days of now is bigger than the days of birth, then diff the two days
-- else add the days of now and the distance from the date of birth to the end of the birth month
select @years,@months,@days -- 0, 11, 28
测试情况
该方法的日子是不同于接受的答案,差异显示在评论如下:
dob now years months days
2012-02-29 2013-02-28 0 11 28 --Days will be 30 if calculated by the approach in accepted answer.
2012-02-29 2016-02-28 3 11 28 --Days will be 31 if calculated by the approach in accepted answer, since the day of birth will be changed to 28 from 29 after dateadd by years.
2012-02-29 2016-03-31 4 1 2
2012-01-30 2016-02-29 4 0 30
2012-01-30 2016-03-01 4 1 2 --Days will be 1 if calculated by the approach in accepted answer, since the day of birth will be changed to 30 from 29 after dateadd by years.
2011-12-30 2016-02-29 4 1 30
一个简短的版本的天通过的情况下声明:
set @days = CASE WHEN day(@now) >= day(@dob) THEN day(@now) - day(@dob)
ELSE @days_in_birth_month - day(@dob) + day(@now) END
如果你想的年龄几年和几个月里,它可能会更简单
set @years = ( @now_i/100 - @dob_i/100)/100
set @months =(12 + month(@now) - month(@dob))%12
select @years,@months -- 1, 0
注: 一个非常有用的链路的 SQL服务器的日期格式
这里是一个(略)更简单的版本:
CREATE PROCEDURE dbo.CalculateAge
@dayOfBirth datetime
AS
DECLARE @today datetime, @thisYearBirthDay datetime
DECLARE @years int, @months int, @days int
SELECT @today = GETDATE()
SELECT @thisYearBirthDay = DATEADD(year, DATEDIFF(year, @dayOfBirth, @today), @dayOfBirth)
SELECT @years = DATEDIFF(year, @dayOfBirth, @today) - (CASE WHEN @thisYearBirthDay > @today THEN 1 ELSE 0 END)
SELECT @months = MONTH(@today - @thisYearBirthDay) - 1
SELECT @days = DAY(@today - @thisYearBirthDay) - 1
SELECT @years, @months, @days
GO
同样的东西作为一个功能。
create function [dbo].[Age](@dayOfBirth datetime, @today datetime)
RETURNS varchar(100)
AS
Begin
DECLARE @thisYearBirthDay datetime
DECLARE @years int, @months int, @days int
set @thisYearBirthDay = DATEADD(year, DATEDIFF(year, @dayOfBirth, @today), @dayOfBirth)
set @years = DATEDIFF(year, @dayOfBirth, @today) - (CASE WHEN @thisYearBirthDay > @today THEN 1 ELSE 0 END)
set @months = MONTH(@today - @thisYearBirthDay) - 1
set @days = DAY(@today - @thisYearBirthDay) - 1
return cast(@years as varchar(2)) + ' years,' + cast(@months as varchar(2)) + ' months,' + cast(@days as varchar(3)) + ' days'
end
create procedure getDatedifference
(
@startdate datetime,
@enddate datetime
)
as
begin
declare @monthToShow int
declare @dayToShow int
--set @startdate='01/21/1934'
--set @enddate=getdate()
if (DAY(@startdate) > DAY(@enddate))
begin
set @dayToShow=0
if (month(@startdate) > month(@enddate))
begin
set @monthToShow= (12-month(@startdate)+ month(@enddate)-1)
end
else if (month(@startdate) < month(@enddate))
begin
set @monthToShow= ((month(@enddate)-month(@startdate))-1)
end
else
begin
set @monthToShow= 11
end
-- set @monthToShow= convert(int, DATEDIFF(mm,0,DATEADD(dd,DATEDIFF(dd,0,@enddate)- DATEDIFF(dd,0,@startdate),0)))-((convert(int,FLOOR(DATEDIFF(day, @startdate, @enddate) / 365.25))*12))-1
if(@monthToShow<0)
begin
set @monthToShow=0
end
declare @amonthbefore integer
set @amonthbefore=Month(@enddate)-1
if(@amonthbefore=0)
begin
set @amonthbefore=12
end
if (@amonthbefore in(1,3,5,7,8,10,12))
begin
set @dayToShow=31-DAY(@startdate)+DAY(@enddate)
end
if (@amonthbefore=2)
begin
IF (YEAR( @enddate ) % 4 = 0 AND YEAR( @enddate ) % 100 != 0) OR YEAR( @enddate ) % 400 = 0
begin
set @dayToShow=29-DAY(@startdate)+DAY(@enddate)
end
else
begin
set @dayToShow=28-DAY(@startdate)+DAY(@enddate)
end
end
if (@amonthbefore in (4,6,9,11))
begin
set @dayToShow=30-DAY(@startdate)+DAY(@enddate)
end
end
else
begin
--set @monthToShow=convert(int, DATEDIFF(mm,0,DATEADD(dd,DATEDIFF(dd,0,@enddate)- DATEDIFF(dd,0,@startdate),0)))-((convert(int,FLOOR(DATEDIFF(day, @startdate, @enddate) / 365.25))*12))
if (month(@enddate)< month(@startdate))
begin
set @monthToShow=12+(month(@enddate)-month(@startdate))
end
else
begin
set @monthToShow= (month(@enddate)-month(@startdate))
end
set @dayToShow=DAY(@enddate)-DAY(@startdate)
end
SELECT
FLOOR(DATEDIFF(day, @startdate, @enddate) / 365.25) as [yearToShow],
@monthToShow as monthToShow ,@dayToShow as dayToShow ,
convert(varchar,FLOOR(DATEDIFF(day, @startdate, @enddate) / 365.25)) +' Year ' + convert(varchar,@monthToShow) +' months '+convert(varchar,@dayToShow)+' days ' as age
return
end
我已经看到的问题多次与输出结果的年、月、日,但从来没有一个数/小的结果。(至少不一,这并不圆错误地).我欢迎这方面的反馈功能。不可能仍然需要一点小小的调整。
--输入功能是两个日期。--输出的数量年两个日期之间在小数(为7.4)格式。-输出是总是,总是一个独到之处的数目。
-注意:输出不处理若差异大于999.9999
--逻辑,是基于三个步骤。--1)差别小于1年(0.5000,为0.3333,0.6667等。) --2)的差别完全是一个整数的年(第1、2、3,等。)
--3)(其他)...差年的一些数天。(到1.5000,2.3333,7.6667等。)
CREATE Function [dbo].[F_Get_Actual_Age](@pi_date1 datetime,@pi_date2 datetime)
RETURNS Numeric(7,4)
AS
BEGIN
Declare
@l_tmp_date DATETIME
,@l_days1 DECIMAL(9,6)
,@l_days2 DECIMAL(9,6)
,@l_result DECIMAL(10,6)
,@l_years DECIMAL(7,4)
--Check to make sure there is a date for both inputs
IF @pi_date1 IS NOT NULL and @pi_date2 IS NOT NULL
BEGIN
IF @pi_date1 > @pi_date2 --Make sure the "older" date is in @pi_date1
BEGIN
SET @l_tmp_date = @pi_date2
SET @pi_date2 = @Pi_date1
SET @pi_date1 = @l_tmp_date
END
--Check #1 If date1 + 1 year is greater than date2, difference must be less than 1 year
IF DATEADD(YYYY,1,@pi_date1) > @pi_date2
BEGIN
--How many days between the two dates (numerator)
SET @l_days1 = DATEDIFF(dd,@pi_date1, @pi_date2)
--subtract 1 year from date2 and calculate days bewteen it and date2
--This is to get the denominator and accounts for leap year (365 or 366 days)
SET @l_days2 = DATEDIFF(dd,dateadd(yyyy,-1,@pi_date2),@pi_date2)
SET @l_years = @l_days1 / @l_days2 -- Do the math
END
ELSE
--Check #2 Are the dates an exact number of years apart.
--Calculate years bewteen date1 and date2, then add the years to date1, compare dates to see if exactly the same.
IF DATEADD(YYYY,DATEDIFF(YYYY,@pi_date1,@pi_date2),@pi_date1) = @pi_date2
SET @l_years = DATEDIFF(YYYY,@pi_date1, @pi_date2) --AS Years, 'Exactly even Years' AS Msg
ELSE
BEGIN
--Check #3 The rest of the cases.
--Check if datediff, returning years, over or under states the years difference
SET @l_years = DATEDIFF(YYYY,@pi_date1, @pi_date2)
IF DATEADD(YYYY,@l_years,@pi_date1) > @pi_date2
SET @l_years = @l_years -1
--use basicly same logic as in check #1
SET @l_days1 = DATEDIFF(dd,DATEADD(YYYY,@l_years,@pi_date1), @pi_date2)
SET @l_days2 = DATEDIFF(dd,dateadd(yyyy,-1,@pi_date2),@pi_date2)
SET @l_years = @l_years + @l_days1 / @l_days2
--SELECT @l_years AS Years, 'Years Plus' AS Msg
END
END
ELSE
SET @l_years = 0 --If either date was null
RETURN @l_Years --Return the result as decimal(7,4)
END
`
很老的问题,但是我想分享我做了什么来计算的年龄
Declare @BirthDate As DateTime
Set @BirthDate = '1994-11-02'
SELECT DATEDIFF(YEAR,@BirthDate,GETDATE()) - (CASE
WHEN MONTH(@BirthDate)> MONTH(GETDATE()) THEN 1
WHEN MONTH(@BirthDate)= MONTH(GETDATE()) AND DAY(@BirthDate) > DAY(GETDATE()) THEN 1
Else 0 END)
有一个简单的方法,根据该时间之间的两天,但与的结束日期截断。
SELECT CAST(DATEDIFF(hour,Birthdate,CAST(GETDATE() as Date))/8766.0 as INT) AS Age FROM <YourTable>
这一个已被证明是非常准确和可靠。如果不是因为内投GETDATE()它可能翻转过生日的前几个小时,午夜,但是,与铸造的,它是死亡年龄的改变过 到底 午夜。
我用这个功能我修改(天一部分)从@丹的回答: https://stackoverflow.com/a/57720/2097023
CREATE FUNCTION dbo.EdadAMD
(
@FECHA DATETIME
)
RETURNS NVARCHAR(10)
AS
BEGIN
DECLARE
@tmpdate DATETIME
, @years INT
, @months INT
, @days INT
, @EdadAMD NVARCHAR(10);
SELECT @tmpdate = @FECHA;
SELECT @years = DATEDIFF(yy, @tmpdate, GETDATE()) - CASE
WHEN (MONTH(@FECHA) > MONTH(GETDATE()))
OR (
MONTH(@FECHA) = MONTH(GETDATE())
AND DAY(@FECHA) > DAY(GETDATE())
) THEN
1
ELSE
0
END;
SELECT @tmpdate = DATEADD(yy, @years, @tmpdate);
SELECT @months = DATEDIFF(m, @tmpdate, GETDATE()) - CASE
WHEN DAY(@FECHA) > DAY(GETDATE()) THEN
1
ELSE
0
END;
SELECT @tmpdate = DATEADD(m, @months, @tmpdate);
IF MONTH(@FECHA) = MONTH(GETDATE())
AND DAY(@FECHA) > DAY(GETDATE())
SELECT @days =
DAY(EOMONTH(GETDATE(), -1)) - (DAY(@FECHA) - DAY(GETDATE()));
ELSE
SELECT @days = DATEDIFF(d, @tmpdate, GETDATE());
SELECT @EdadAMD = CONCAT(@years, 'a', @months, 'm', @days, 'd');
RETURN @EdadAMD;
END;
GO
它工作得很好。
你是试图计算出的总天数/月/年的一年龄?你有一个起始日期?或者是你想剖析(例如:24年1月29日)?
如果你有一个开始日期,你在工作,datediff将输出的总天数/月/年与以下命令:
Select DateDiff(d,'1984-07-12','2008-09-11')
Select DateDiff(m,'1984-07-12','2008-09-11')
Select DateDiff(yyyy,'1984-07-12','2008-09-11')
与相应的输出(8827/290/24).
现在,如果你想要做的解剖方法,你已经减去的数年中的几天(日-365*年),然后再做进一步的数学上那得几个月,等等。
这里是SQL的代码给你的数量的年、月、日子以来的sysdate.输入的价值input_birth_date这种格式(dd_mon_yy).注:输入相同的价值(出生日期)几年、几个月&天如01-mar-85
select trunc((sysdate -to_date('&input_birth_date_dd_mon_yy'))/365) years,
trunc(mod(( sysdate -to_date('&input_birth_date_dd_mon_yy'))/365,1)*12) months,
trunc((mod((mod((sysdate -to_date('&input_birth_date_dd_mon_yy'))/365,1)*12),1)*30)+1) days
from dual
DateTime
值在T-SQL被储存作为浮动。你可以只删减的日期,从每一个其他的,你现在有一个新的日期之间的时间跨度。
declare @birthdate datetime
set @birthdate = '6/15/1974'
--age in years - short version
print year(getdate() - @birthdate) - year(0)
--age in years - visualization
declare @mindate datetime
declare @span datetime
set @mindate = 0
set @span = getdate() - @birthdate
print @mindate
print @birthdate
print getdate()
print @span
--substract minyear from spanyear to get age in years
print year(@span) - year(@mindate)
print month(@span)
print day(@span)
CREATE FUNCTION DBO.GET_AGE
(
@DATE AS DATETIME
)
RETURNS VARCHAR(MAX)
AS
BEGIN
DECLARE @YEAR AS VARCHAR(50) = ''
DECLARE @MONTH AS VARCHAR(50) = ''
DECLARE @DAYS AS VARCHAR(50) = ''
DECLARE @RESULT AS VARCHAR(MAX) = ''
SET @YEAR = CONVERT(VARCHAR,(SELECT DATEDIFF(MONTH,CASE WHEN DAY(@DATE) > DAY(GETDATE()) THEN DATEADD(MONTH,1,@DATE) ELSE @DATE END,GETDATE()) / 12 ))
SET @MONTH = CONVERT(VARCHAR,(SELECT DATEDIFF(MONTH,CASE WHEN DAY(@DATE) > DAY(GETDATE()) THEN DATEADD(MONTH,1,@DATE) ELSE @DATE END,GETDATE()) % 12 ))
SET @DAYS = DATEDIFF(DD,DATEADD(MM,CONVERT(INT,CONVERT(INT,@YEAR)*12 + CONVERT(INT,@MONTH)),@DATE),GETDATE())
SET @RESULT = (RIGHT('00' + @YEAR, 2) + ' YEARS ' + RIGHT('00' + @MONTH, 2) + ' MONTHS ' + RIGHT('00' + @DAYS, 2) + ' DAYS')
RETURN @RESULT
END
SELECT DBO.GET_AGE('04/12/1986')
DECLARE @BirthDate datetime, @AgeInMonths int
SET @BirthDate = '10/5/1971'
SET @AgeInMonths -- Determine the age in "months old":
= DATEDIFF(MONTH, @BirthDate, GETDATE()) -- .Get the difference in months
- CASE WHEN DATEPART(DAY,GETDATE()) -- .If today was the 1st to 4th,
< DATEPART(DAY,@BirthDate) -- (or before the birth day of month)
THEN 1 ELSE 0 END -- ... don't count the month.
SELECT @AgeInMonths / 12 as AgeYrs -- Divide by 12 months to get the age in years
,@AgeInMonths % 12 as AgeXtraMonths -- Get the remainder of dividing by 12 months = extra months
,DATEDIFF(DAY -- For the extra days, find the difference between,
,DATEADD(MONTH, @AgeInMonths -- 1. Last Monthly Birthday
, @BirthDate) -- (if birthdays were celebrated monthly)
,GETDATE()) as AgeXtraDays -- 2. Today's date.
对于那些想要建立一个计算列表中储存的年龄:
CASE WHEN DateOfBirth< DATEADD(YEAR, (DATEPART(YEAR, GETDATE()) - DATEPART(YEAR, DateOfBirth))*-1, GETDATE())
THEN DATEPART(YEAR, GETDATE()) - DATEPART(YEAR, DateOfBirth)
ELSE DATEPART(YEAR, GETDATE()) - DATEPART(YEAR, DateOfBirth) -1 END
这里是我如何计算给定年龄的出生日期和目前的日期。
select case
when cast(getdate() as date) = cast(dateadd(year, (datediff(year, '1996-09-09', getdate())), '1996-09-09') as date)
then dateDiff(yyyy,'1996-09-09',dateadd(year, 0, getdate()))
else dateDiff(yyyy,'1996-09-09',dateadd(year, -1, getdate()))
end as MemberAge
go
还有另一种方法计算的年龄
请参阅以下表
FirstName LastName DOB
sai krishnan 1991-11-04
Harish S A 1998-10-11
为找到的年龄,可以计算通过一个月
Select datediff(MONTH,DOB,getdate())/12 as dates from [Organization].[Employee]
结果会是
firstname dates
sai 27
Harish 20
declare @StartDate datetime = '2016-01-31'
declare @EndDate datetime = '2016-02-01'
SELECT @StartDate AS [StartDate]
,@EndDate AS [EndDate]
,DATEDIFF(Year,@StartDate,@EndDate) - CASE WHEN DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate), @StartDate) > @EndDate THEN 1 ELSE 0 END AS [Years]
,DATEDIFF(Month,(DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate) - CASE WHEN DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate), @StartDate) > @EndDate THEN 1 ELSE 0 END,@StartDate)),@EndDate) - CASE WHEN DATEADD(Month, DATEDIFF(Month,DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate) - CASE WHEN DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate), @StartDate) > @EndDate THEN 1 ELSE 0 END,@StartDate),@EndDate) , @StartDate) > @EndDate THEN 1 ELSE 0 END AS [Months]
,DATEDIFF(Day, DATEADD(Month,DATEDIFF(Month, (DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate) - CASE WHEN DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate), @StartDate) > @EndDate THEN 1 ELSE 0 END,@StartDate)),@EndDate) - CASE WHEN DATEADD(Month, DATEDIFF(Month,DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate) - CASE WHEN DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate), @StartDate) > @EndDate THEN 1 ELSE 0 END,@StartDate),@EndDate) , @StartDate) > @EndDate THEN 1 ELSE 0 END ,DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate) - CASE WHEN DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate), @StartDate) > @EndDate THEN 1 ELSE 0 END,@StartDate)) ,@EndDate) - CASE WHEN DATEADD(Day,DATEDIFF(Day, DATEADD(Month,DATEDIFF(Month, (DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate) - CASE WHEN DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate), @StartDate) > @EndDate THEN 1 ELSE 0 END,@StartDate)),@EndDate) - CASE WHEN DATEADD(Month, DATEDIFF(Month,DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate) - CASE WHEN DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate), @StartDate) > @EndDate THEN 1 ELSE 0 END,@StartDate),@EndDate) , @StartDate) > @EndDate THEN 1 ELSE 0 END ,DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate) - CASE WHEN DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate), @StartDate) > @EndDate THEN 1 ELSE 0 END,@StartDate)) ,@EndDate),DATEADD(Month,DATEDIFF(Month, (DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate) - CASE WHEN DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate), @StartDate) > @EndDate THEN 1 ELSE 0 END,@StartDate)),@EndDate) - CASE WHEN DATEADD(Month, DATEDIFF(Month,DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate) - CASE WHEN DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate), @StartDate) > @EndDate THEN 1 ELSE 0 END,@StartDate),@EndDate) , @StartDate) > @EndDate THEN 1 ELSE 0 END ,DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate) - CASE WHEN DATEADD(Year,DATEDIFF(Year,@StartDate,@EndDate), @StartDate) > @EndDate THEN 1 ELSE 0 END,@StartDate))) > @EndDate THEN 1 ELSE 0 END AS [Days]
select DOB as Birthdate,
YEAR(GETDATE()) as ThisYear,
YEAR(getdate()) - EAR(date1) as Age
from TableName
SELECT DOB AS Birthdate ,
YEAR(GETDATE()) AS ThisYear,
YEAR(getdate()) - YEAR(DOB) AS Age
FROM tableprincejain
DECLARE @DoB AS DATE = '1968-10-24'
DECLARE @cDate AS DATE = CAST('2000-10-23' AS DATE)
SELECT
--Get Year difference
DATEDIFF(YEAR,@DoB,@cDate) -
--Cases where year difference will be augmented
CASE
--If Date of Birth greater than date passed return 0
WHEN YEAR(@DoB) - YEAR(@cDate) >= 0 THEN DATEDIFF(YEAR,@DoB,@cDate)
--If date of birth month less than date passed subtract one year
WHEN MONTH(@DoB) - MONTH(@cDate) > 0 THEN 1
--If date of birth day less than date passed subtract one year
WHEN MONTH(@DoB) - MONTH(@cDate) = 0 AND DAY(@DoB) - DAY(@cDate) > 0 THEN 1
--All cases passed subtract zero
ELSE 0
END