From Roy Hann@21:1/5 to All on Wed Oct 27 19:53:09 2021
I'm well used to doing arithmetic with the native Ingres DATE
(INGRESDATE) type, e.g.:
SELECT birthdate + '3 months' FROM...
If birthdate is an ANSI date (ANSIDATE) the above still works
perfectly well.
But I doubt that is idiomatic ISO/ANSI SQL. I've Googled a bit and found
all kinds of syntax being used. I suspect ...+'3 months' or ...-'49
days' might not work reliably outside of Ingres.
So is there anything that does work reliably? Google is not being super
helpful on this... Maybe I haven't guessed the best search term
though.