select  add_months(current_date, -1)  as next_previous, add_months(current_date, 1) as next_month

output:
  	next_previous	next_month
	03/15/2011	05/15/2011

add day

select current_date -1 as yesterday, current_date as today, current_date +1 as tomorrow

output:
 	yesterday	today	tomorrow
	04/14/2011	04/15/2011	04/16/2011