Calculate age using 3 columns representing year, month and date

Question

I have 3 columns dob_year, dob_month, dob_day, all 3 columns are data type nvarchar(50). when I try to calculate age comparing dob (date of birth) with gatedate() I will get message "Conversion failed when converting date and/or time from character string.".

DATEDIFF(yy, (s.dob_year+'-'+s.dob_month+'-'+s.dob_day), GETDATE())as age, 

I tried to use same function together with convert() or cast() functions I will get same message.

Answer 1

Your syntax suggests that you are using SQL Server. If your values are all ok, you can use:

datefromparts(s.dob_year, s.dob_month, s.dob_day)

However, if you have bad combinations (such as Feb 31st), then you need a TRY_ function. For that, I would suggest:

try_convert(date, convert(varchar(8), s.dob_year * 10000 + s.dob_year * 100 + s.dob_day))

This puts the three columns in the format YYYYMMDD, which can then be converted readily to a date.