Calculate age from a varchar birthdate field

nuttylife2 · March 8th, 2006, 10:02 PM

I will really appreciate any help you can give me. Thanks Gert;
The format of my string is mm/dd/yyyy, I tried actually changing the field directly in the database design but I am getting the error:
Syntax error converting datetime from character string.

Quote:

quote:
Originally posted by Gert
Hi.

If you could answer my question "What is the format of the date of birth string?", then we might be able to help.
You say it is in format "08/08/1965", but that doesn't tell us mutch. What is the date-part and what is the month-part?
In your example the result will always be august 8th 1965, but how would you write august 20th 1965 in your format?
"20/08/1965" or "08/20/1965" ?

Also: what errormessages do you get from the functions?

Gert

Gert · March 9th, 2006, 09:41 AM

Hi again.

You should be able to use JoeFlow's function as it is. Try it out in a select. If it doesn't work, try setting the date format lik this:
SET DATEFORMAT mdy

If it works after you have done that, then maybe your default dateformat on the server is not what you think it is..

Gert

rgerald · March 9th, 2006, 12:10 PM

WARNING:

JoeFlow's CalculateAge function DOES NOT WORK

Try Rand's f_AgeCalc instead.

Test Results -- Errors marked with <<<

Test f_AgeCalc
ID Birth Date Age
----------- ---------- -----------
          1 01/01/2001 5
          2 02/29/2004 2
          3 03/01/2004 2
          4 03/02/2004 2
          5 03/01/2000 6
          6 12/31/1999 6
          7 04/01/2003 2
          8 02/07/1998 8
          9 12/24/1937 68
         10 05/08/1948 57
         11 03/03/2003 3
         12 02/29/1960 46
         13 03/09/1991 15
         14 03/10/1991 14

(14 row(s) affected)

Test CalculateAge
ID Birth Date Age
----------- ---------- -----------
          1 01/01/2001 4 <<<
          2 02/29/2004 1 <<<
          3 03/01/2004 1 <<<
          4 03/02/2004 1 <<<
          5 03/01/2000 5 <<<
          6 12/31/1999 6
          7 04/01/2003 2
          8 02/07/1998 7 <<<
          9 12/24/1937 68
         10 05/08/1948 57
         11 03/03/2003 2 <<<
         12 02/29/1960 45 <<<
         13 03/09/1991 14 <<<
         14 03/10/1991 14

(14 row(s) affected)

Rand

Jeff Mason · March 9th, 2006, 01:46 PM

I think you can also get that "Syntax error..." if the varchar column in the table cannot be converted to a valid date via the CONVERT function.

Try:

Code:

SELECT birthdt, ...
  FROM yourtable
 WHERE ISDATE(birthdt) = 0

to see if there are any such values.

Your column may contain values like '12/31/2005' and '31/12/2005' which are perfectly legitimate strings, but, depending on how your server is configured, one or the other is always an invalid date. Your column could also contain total junk like 'mm/dd/yyyy', or 'HELLO WORLD'.

You need to find the person who designed this table to have dates stored as a character string, take them out back and shoot them. Next, convert this character string column to a datetime datatype. You'll find that it is much easier to manipulate dates when they are, er, dates.

Jeff Mason
Custom Apps, Inc.
www.custom-apps.com

sshelper · March 17th, 2006, 12:35 PM

Here's a link to another user-defined function that computes for a date given the birthdate:

http://www.sql-server-helper.com/functions/get-age.aspx

SQL Server Helper
http://www.sql-server-helper.com

hrothenb · April 18th, 2016, 10:56 AM

Code:

CREATE FUNCTION [dbo].[ufn_GetAge]
(@pDateOfBirth DATETIME,
 @pAsOfDate    DATETIME
)
RETURNS INT
AS
     BEGIN
         DECLARE @vAge INT;
         IF @pDateOfBirth >= @pAsOfDate
             RETURN 0;
         SET @vAge = DATEDIFF(YY, @pDateOfBirth, @pAsOfDate);
         IF MONTH(@pDateOfBirth) > MONTH(@pAsOfDate)
            OR (MONTH(@pDateOfBirth) = MONTH(@pAsOfDate)
                AND DAY(@pDateOfBirth) > DAY(@pAsOfDate))
             SET @vAge = @vAge - 1;
         RETURN @vAge;
     END;
GO