Is there some way to write a function that converts a date that is in seconds since December 31, 1969, into a normal date format?
Like this: date from (900,973,200) in seconds to (YYYY,MM,DD) or any normal format.
The dateadd funtion takes three arguments: the date part, a number, and a date. It then adds the number to the date and returns a datetime as a result.
In your case, to specify that you are adding seconds you would use ss for the datepart. So:
select dateadd (ss,900973200,'December 31,1969')
You can encapsulate this code in a stored procedure if you'd like.