How can i select all dates between date range? - range

I have one SQL Table with 2 columns as below
Column1: ProductionDate - DateTime - Not NULL
Column2: Quantity - Int - Not NULL
Now There are 2 Records in Table
1-1-2012, 5
1-3-2012, 7
Output of Result should be as below if i give date range StartDate as 1-1-2012 and EndDate as 1-15-2012
1-1-2012 5
1-2-2012 0
1-3-2012 7
1-4-2012 0
1-5-2012 0
1-6-2012 0
.
.
.
1-15-2012 0
Means Query should return all the dates of given range with Quantity and if no entry in Table then 0 for Quantity.
How to Do it? Please suggest with Query


Here's one very optimistic draft on what you can use ( source - here )
declare #startDate datetime;
declare #endDate datetime;
set #startDate = '2012-02-09';
set #endDate = '2012-02-15';
WITH span AS (
SELECT #startDate AS dt
UNION ALL
SELECT DATEADD(dd, 1, dt)
FROM span s
WHERE DATEADD(dd, 1, dt) <= #endDate)
select s.dt, t.Quantity from span s
join table t
on s.dt = t.ProductionDate

Related

How to find the First, Second, Third and Fourth Saturday in month?

How do I find the first, second, third and fourth saturday of the month?
Ex.: I want to end up with this format...
Blockquote
YYYY, MM, Week#1
Blockquote
YYYY, MM, Week#2
Blockquote
Thanks,

This solution does not depend on Datefirst setting.
declare #d datetime = getdate();
select
dateadd(dd, n, firstSaturday)
from (
select
firstSaturday = dateadd(day, 7-(##datefirst+datepart(weekday, dateadd(day,-1, convert(char(6),#d,112)+'01')))%7, dateadd(day,-1, convert(char(6),#d,112)+'01'))
) t
cross apply (values (0), (7), (14), (21)) q(n)

Here is one way to do it, using a stacked cte to create an inline tally table, with another cte on top of that to generate the months calendar.
Please note that you can change the GETDATE() in the first row code to any date you want (even if it's in the middle of the month) and the code will produce all the Saturdays in that month.
-- Get the current month's start date
DECLARE #MonthStart datetime = DATEADD(MONTH, (DATEDIFF(MONTH, 0, GETDATE())), 0)
;WITH lv0 AS (SELECT 0 g UNION ALL SELECT 0)
,lv1 AS (SELECT 0 g FROM lv0 a CROSS JOIN lv0 b) -- 4
,lv2 AS (SELECT 0 g FROM lv1 a CROSS JOIN lv1 b) -- 16
,lv3 AS (SELECT 0 g FROM lv2 a CROSS JOIN lv2 b) -- 256
,Tally (n) AS (SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM lv3)
-- gets all the dates in the current month
,CurrentMonth AS (SELECT TOP (32) dateadd(day, n-1, #MonthStart) As TheDate
FROM Tally
WHERE MONTH(dateadd(day, n-1, #MonthStart)) = MONTH(#MonthStart)
ORDER BY n)
-- gets all the Saturday dates of the current month
SELECT TheDate, DATENAME(WEEKDAY, TheDate)
FROM CurrentMonth
WHERE DATEPART(WEEKDAY, TheDate) = 7 -- Depending on server settings!
If you already have a numbers table, you can use it instead of the stacked cte. If you don't know what is a numbers table and why you should have one, read The "Numbers" or "Tally" Table: What it is and how it replaces a loop by Jeff Moden

You can try this.
SET DATEFIRST 1
DECLARE #MonthId INT = 5
DECLARE #FirstDayOfTheMonth DATE = CONCAT(YEAR(GETDATE()), RIGHT(CONCAT('00', #MonthId),2), '01')
DECLARE #SaturdayId INT = 6
SELECT
DATEADD(DAY, #SaturdayId + WK.ID - DATEPART(WEEKDAY, #FirstDayOfTheMonth), #FirstDayOfTheMonth)
FROM ( VALUES(0),(7),(14),(21),(28)) AS WK(ID)
WHERE
MONTH(DATEADD(DAY, #SaturdayId + WK.ID- DATEPART(WEEKDAY, #FirstDayOfTheMonth),#FirstDayOfTheMonth)) = #MonthId

Find total number in a specific period of time SQL

I am trying to find the total number of members in a given period. Say I have the following data:
member_id start_date end_date
1 9/1/2013 12/31/2013
2 10/1/2013 11/12/2013
3 12/1/2013 12/31/2013
4 5/1/2012 8/5/2013
5 9/1/2013 12/31/2013
6 7/1/2013 12/31/2013
7 6/6/2012 12/5/2013
8 10/1/2013 12/31/2013
9 7/8/2013 12/31/2013
10 1/1/2012 11/5/2013
In SQL I need to create a report that will list out the number of members in each month of the year. In this case something like the following:
Date Members Per Month
Jan-12 1
Feb-12 1
Mar-12 1
Apr-12 1
May-12 2
Jun-12 3
Jul-12 3
Aug-12 3
Sep-12 3
Oct-12 3
Nov-12 3
Dec-12 3
Jan-13 3
Feb-13 3
Mar-13 3
Apr-13 3
May-13 3
Jun-13 3
Jul-13 5
Aug-13 4
Sep-13 6
Oct-13 8
Nov-13 6
Dec-13 6
So there is only 1 member from Jan-12 (member id 10) until May-12 when member id 4 joins making the count 2 and so on.
The date range can be all over so I can't specify the specific dates but it is by month, meaning that even if someone ends 12-1 it is considered active for the month for Dec.

I was able to create the following stored procedure that was able to accomplish what I needed:
USE [ValueBasedSandbox]
GO
/****** Object: StoredProcedure [dbo].[sp_member_count_per_month] Script Date: 01/08/2015 12:02:37 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Create date: 2015-08-01
-- Description: Find the counts per a given date passed in
-- =============================================
CREATE PROCEDURE [dbo].[sp_member_count_per_month]
-- Add the parameters for the stored procedure here
#YEAR int
, #ENDYEAR int
AS
DECLARE #FIRSTDAYMONTH DATETIME
DECLARE #LASTDAYMONTH DATETIME
DECLARE #MONTH INT = 1;
--Drop the temporary holding table if exists
IF OBJECT_ID('tempdb.dbo.##TEMPCOUNTERTABLE', 'U') IS NOT NULL
DROP TABLE dbo.##TEMPCOUNTERTABLE
CREATE TABLE dbo.##TEMPCOUNTERTABLE (
counter INT
, start_date DATETIME2
, end_date DATETIME2
)
--Perform this loop for each year desired
WHILE #YEAR <= #ENDYEAR
BEGIN
--Perform for each month of the year
WHILE (#MONTH <= 12)
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
SET #FIRSTDAYMONTH = DATEADD(MONTH, #MONTH - 1, DATEADD(YEAR, #YEAR-1900, 0))
SET #LASTDAYMONTH = DATEADD(MONTH, #MONTH, DATEADD(YEAR, #YEAR-1900, 0)-1)
INSERT INTO dbo.##TEMPCOUNTERTABLE(counter, start_date, end_date)
SELECT COUNT(*) AS counter
, #FIRSTDAYMONTH AS start_date
, #LASTDAYMONTH AS end_date
FROM dbo.member_table
WHERE start_date <= #LASTDAYMONTH
AND end_date >= #FIRSTDAYMONTH
--Increment through all the months of the year
SET #MONTH = #MONTH + 1
END -- End Monthly Loop
--Reset Month counter
SET #MONTH = 1
--Increment the desired years
SET #YEAR = #YEAR + 1
END -- End Yearly Loop
--Display the results
SELECT *
FROM dbo.##TEMPCOUNTERTABLE
-- Drop the temp table
IF OBJECT_ID('tempdb.dbo.##TEMPCOUNTERTABLE', 'U') IS NOT NULL
DROP TABLE dbo.##TEMPCOUNTERTABLE
GO

This should do the trick
with datesCte(monthStart,monthEnd) as
(
select cast('20120101' as date) as monthStart, cast('20120131' as date) as monthEnd
union all
select DATEADD(MONTH, 1, d.monthStart), dateadd(day, -1, dateadd(month, 1, d.monthStart))
from datesCte as d
where d.monthStart < '20140101'
)
select *
from datesCte as d
cross apply
(
select count(*) as cnt
from dbo.MemberDates as m
where m.startDate <= d.monthEnd and m.endDate > d.monthStart
) as x
order by d.monthStart

Yearly total for items over multiple years

I am trying to find the total per year
For example
Start date End Date Total Value
1 07/01/14 01/01/15 $10,000
2 08/01/13 12/01/14 $10,000
3 03/01/13 05/01/15 $10,000
As you can see, Some items are over multiple years. Is there a way to find out what the total value is per year.
Solution should be:
item 3
2013- $3600
2014-$4800
2015-1600
Then a summation would be down for all three items to give a yearly total.
What I have so far:
I have a rolling summation code which is shown below.
case when
(
[begin date] >= dateadd(mm,0,DATEADD(mm,DATEDIFF(mm,0,getdate()),0))
and [end date] >= dateadd(mm,0,DATEADD(mm,DATEDIFF(mm,0,getdate()),0))
)
OR
(
[Begin Date] < dateadd(mm,0,DATEADD(mm,DATEDIFF(mm,0,getdate()),0))
and [End Date] >= dateadd(mm,0,DATEADD(mm,DATEDIFF(mm,0,getdate()),0))
)
then [Totalvalue]/nullif(DATEDIFF(mm,[begin date],[end date]),0)
else 0
end [Current Month]

I dono how you got that total values for item 3
but for item 3 i hope it should be
2013 = 3704
2014 = 4444
2015 = 1852
Dono how efficient this code is just have a try
CREATE TABLE #tblName
(
itemid INT,
startdate DATETIME,
endate DATETIME,
value int
)
INSERT INTO #tblName
VALUES (1,'2014/07/01','2015/01/01',10000),
(2,'2013/08/01','2014/12/01',10000),
(3,'2013/03/01','2015/05/01',10000)
DECLARE #mindate DATETIME,
#maxdate DATETIME
SELECT #mindate = Min(startdate),
#maxdate = Max(endate)
FROM #tblName
SELECT *
FROM #tblName;
WITH cte
AS (SELECT #mindate startdate
UNION ALL
SELECT Dateadd(mm, 1, startdate) startdate
FROM cte
WHERE startdate <= Dateadd(mm, -1, #maxdate))
SELECT a.value * ( ( convert(numeric(22,6),a.cnt) / convert(numeric(22,6),c.total) ) * 100 ) / 100,a.itemid,a.startdate
FROM (SELECT Avg(value) value,
Count(1) cnt,
itemid,
Year(a.startdate) startdate
FROM cte a
JOIN #tblName b
ON a.startdate BETWEEN b.startdate AND b.endate
GROUP BY itemid,
Year(a.startdate)) a
JOIN(SELECT Sum(cnt) total,
itemid
FROM (SELECT Avg(value) value,
Count(1) cnt,
itemid,
Year(a.startdate) startdate
FROM cte a
JOIN #tblName b
ON a.startdate BETWEEN b.startdate AND b.endate
GROUP BY itemid,
Year(a.startdate)) B
GROUP BY itemid) C
ON a.itemid = c.itemid
WHERE a.itemid = 3

How do you calculate the number of weeks between two dates?

How do you calculate the number of weeks between two dates?
for example as follows
Declare #StartDate as DateTime = "01 Jan 2009";
Declare #EndDate as DateTime = "01 June 2009";
#StartDate and #EndDate

Use the Datediff function. datediff(ww,#startdate,#enddate)
the ww tells the function what units you require the difference to be counted in.
http://msdn.microsoft.com/en-us/library/ms189794.aspx

You may use the following function to retrives week's between two dates:
CREATE FUNCTION [dbo].[fGetWeeksList]
(
#StartDate DATETIME
,#EndDate DATETIME
)
RETURNS
TABLE
AS
RETURN
(
SELECT DATEADD(DAY,-(DATEPART(DW,DATEADD(WEEK, x.number, #StartDate))-2),DATEADD(WEEK, x.number, #StartDate)) as [StartDate]
,DATEADD(DAY,-(DATEPART(DW,DATEADD(WEEK, x.number + 1, #StartDate))-1) ,DATEADD(WEEK, x.number + 1, #StartDate)) AS [EndDate]
FROM master.dbo.spt_values x
WHERE x.type = 'P' AND x.number <= DATEDIFF(WEEK, #StartDate, DATEADD(WEEK,0,CAST(#EndDate AS DATE)))

How to calculate age in T-SQL with years, months, and days

What would be the best way to calculate someone's age in years, months, and days in T-SQL (SQL Server 2000)?
The datediff function doesn't handle year boundaries well, plus getting the months and days separate will be a bear. I know I can do it on the client side relatively easily, but I'd like to have it done in my stored procedure.

Here is some T-SQL that gives you the number of years, months, and days since the day specified in #date. It takes into account the fact that DATEDIFF() computes the difference without considering what month or day it is (so the month diff between 8/31 and 9/1 is 1 month) and handles that with a case statement that decrements the result where appropriate.
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

Try this...
SELECT CASE WHEN
(DATEADD(year,DATEDIFF(year, #datestart ,#dateend) , #datestart) > #dateend)
THEN DATEDIFF(year, #datestart ,#dateend) -1
ELSE DATEDIFF(year, #datestart ,#dateend)
END
Basically the "DateDiff( year...", gives you the age the person will turn this year, so i have just add a case statement to say, if they have not had a birthday yet this year, then subtract 1 year, else return the value.

Simple way to get age as text is as below:
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
Results Format will be:
**63 Y & 2 M**

Implemented by arithmetic with ISO formatted date.
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
Test Cases
The approach of days is different from the accepted answer, the differences shown in the comments below:
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
An short version of Days by case statement:
set #days = CASE WHEN day(#now) >= day(#dob) THEN day(#now) - day(#dob)
ELSE #days_in_birth_month - day(#dob) + day(#now) END
If you want the age of years and months only, it could be simpler
set #years = ( #now_i/100 - #dob_i/100)/100
set #months =(12 + month(#now) - month(#dob))%12
select #years,#months -- 1, 0
NOTE: A very useful link of SQL Server Date Formats

Here is a (slightly) simpler version:
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

The same sort of thing as a function.
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

I use this Function I modified (the Days part) From #Dane answer: 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
It works pretty well.

I've seen the question several times with results outputting Years, Month, Days but never a numeric / decimal result. (At least not one that doesn't round incorrectly).
I welcome feedback on this function. Might not still need a little adjusting.
-- Input to the function is two dates.
-- Output is the numeric number of years between the two dates in Decimal(7,4) format.
-- Output is always always a possitive number.
-- NOTE:Output does not handle if difference is greater than 999.9999
-- Logic is based on three steps.
-- 1) Is the difference less than 1 year (0.5000, 0.3333, 0.6667, ect.)
-- 2) Is the difference exactly a whole number of years (1,2,3, ect.)
-- 3) (Else)...The difference is years and some number of days. (1.5000, 2.3333, 7.6667, ect.)
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
`

Quite Old question, but I want to share what I have done to calculate age
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)

Are you trying to calculate the total days/months/years of an age? do you have a starting date? Or are you trying to dissect it (ex: 24 years, 1 month, 29 days)?
If you have a start date that you're working with, datediff will output the total days/months/years with the following commands:
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')
with the respective outputs being (8827/290/24).
Now, if you wanted to do the dissection method, you'd have to subtract the number of years in days (days - 365*years), and then do further math on that to get the months, etc.

Here is SQL code that gives you the number of years, months, and days since the sysdate.
Enter value for input_birth_date this format(dd_mon_yy). note: input same value(birth date) for years, months & days such as 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 values in T-SQL are stored as floats. You can just subtract the dates from each other and you now have a new date that is the timespan between them.
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.

For the ones that want to create a calculated column in a table to store the age:
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

There is an easy way, based on the hours between the two days BUT with the end date truncated.
SELECT CAST(DATEDIFF(hour,Birthdate,CAST(GETDATE() as Date))/8766.0 as INT) AS Age FROM <YourTable>
This one has proven to be extremely accurate and reliable. If it weren't for the inner CAST on the GETDATE() it might flip the birthday a few hours before midnight but, with the CAST, it is dead on with the age changing over at exactly midnight.

Here is how I calculate the age given a birth date and the current date.
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

There is another method for calculate age is
See below table
FirstName LastName DOB
sai krishnan 1991-11-04
Harish S A 1998-10-11
For finding age,you can calculate through month
Select datediff(MONTH,DOB,getdate())/12 as dates from [Organization].[Employee]
Result will be
firstname dates
sai 27
Harish 20

I have created a function calculateAge that takes parameter dateOfBirth from outside and then it calculates the age in years, months and days and finally it returns in string format.
CREATE FUNCTION calculateAge(dateOfBirth datetime) RETURNS varchar(40)
BEGIN
set #currentdatetime = CURRENT_TIMESTAMP;
set #years = TIMESTAMPDIFF(YEAR,dateOfBirth,#currentdatetime);
set #months = TIMESTAMPDIFF(MONTH,dateOfBirth,#currentdatetime) - #years*12 ;
set #dayOfBirth = EXTRACT(DAY FROM dateOfBirth);
set #today = EXTRACT(DAY FROM #currentdatetime);
set #days = 0;
if (#today > #dayOfBirth) then
set #days = #today - #dayOfBirth;
else
set #decreaseMonth = DATE_SUB(#currentdatetime, INTERVAL 1 MONTH);
set #days = DATEDIFF(dateOfBirth, #decreaseMonth);
end if;
RETURN concat(concat( concat(#years , "years\n") , concat(#months , "months\n")), concat(#days , "days"));
END

Plenty of solutions have been given already, but I beleive this one to be both easy to understand and reliable, as it will handle leap years as well :
case when datepart(dayofyear, #birth) <= datepart(dayofyear, getdate())
then datepart(year, getdate()) - datepart(year, #birth)
else datepart(year, getdate()) - datepart(year, #birth) - 1
end
The idea is to simply compute the difference in years between the two years (birth and now), and substract 1 if the anniversary has not been reached for the current year.

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

declare #BirthDate datetime
declare #TotalYear int
declare #TotalMonths int
declare #TotalDays int
declare #TotalWeeks int
declare #TotalHours int
declare #TotalMinute int
declare #TotalSecond int
declare #CurrentDtTime datetime
set #BirthDate='1998/01/05 05:04:00' -- Set Your date here
set #TotalYear= FLOOR(DATEDIFF(DAY, #BirthDate, GETDATE()) / 365.25)
set #TotalMonths= FLOOR(DATEDIFF(DAY,DATEADD(year, #TotalYear,#BirthDate),GetDate()) / 30.436875E)
set #TotalDays= FLOOR(DATEDIFF(DAY, DATEADD(month, #TotalMonths,DATEADD(year,
#TotalYear,#BirthDate)), GETDATE()))
set #CurrentDtTime=CONVERT(datetime,CONVERT(varchar(50), DATEPART(year,
GetDate()))+'/' +CONVERT(varchar(50), DATEPART(MONTH, GetDate()))
+'/'+ CONVERT(varchar(50),DATEPART(DAY, GetDate()))+' '
+ CONVERT(varchar(50),DATEPART(HOUR, #BirthDate))+':'+
CONVERT(varchar(50),DATEPART(MINUTE, #BirthDate))+
':'+ CONVERT(varchar(50),DATEPART(Second, #BirthDate)))
set #TotalHours = DATEDIFF(hour, #CurrentDtTime, GETDATE())
if(#TotalHours < 0)
begin
set #TotalHours = DATEDIFF(hour,DATEADD(Day,-1, #CurrentDtTime), GETDATE())
set #TotalDays= #TotalDays -1
end
set #TotalMinute= DATEPART(MINUTE, GETDATE())-DATEPART(MINUTE, #BirthDate)
if(#TotalMinute < 0)
set #TotalMinute = DATEPART(MINUTE, DATEADD(hour,-1,GETDATE()))+(60-DATEPART(MINUTE,
#BirthDate))
set #TotalSecond= DATEPART(Second, GETDATE())-DATEPART(Second, #BirthDate)
Print 'Your age are'+ CHAR(13)
+ CONVERT(varchar(50), #TotalYear)+' Years, ' +
CONVERT(varchar(50),#TotalMonths) +' Months, ' +
CONVERT(varchar(50),#TotalDays)+' Days, ' +
CONVERT(varchar(50),#TotalHours)+' Hours, ' +
CONVERT(varchar(50),#TotalMinute)+' Minutes, ' +
CONVERT(varchar(50),#TotalSecond)+' Seconds. ' +char(13)+
'Your are born at day of week was - ' + CONVERT(varchar(50),DATENAME(dw ,
#BirthDate ))
+char(13)+char(13)+
+'Your Birthdate to till date your '+ CHAR(13)
+'Years - ' + CONVERT(varchar(50), FLOOR(DATEDIFF(DAY, #BirthDate, GETDATE()) /
365.25))
+' , Months - ' + CONVERT(varchar(50),DATEDIFF(MM,#BirthDate,getdate()))
+' , Weeks - ' + CONVERT(varchar(50),DATEDIFF(wk,#BirthDate,getdate()))
+' , Days - ' + CONVERT(varchar(50),DATEDIFF(dd,#BirthDate,getdate()))+char(13)+
+'Hours - ' + CONVERT(varchar(50),DATEDIFF(HH,#BirthDate,getdate()))
+' , Minutes - ' + CONVERT(varchar(50),DATEDIFF(mi,#BirthDate,getdate()))
+' , Seconds - ' + CONVERT(varchar(50),DATEDIFF(ss,#BirthDate,getdate()))
Output
Your age are
22 Years, 0 Months, 2 Days, 11 Hours, 30 Minutes, 16 Seconds.
Your are born at day of week was - Monday
Your Birthdate to till date your
Years - 22 , Months - 264 , Weeks - 1148 , Days - 8037
Hours - 192899 , Minutes - 11573970 , Seconds - 694438216