Months between two dates function

Question

In oracle i can find out no:of months between using MONTHS_BETWEEN function.

In postgres i am using extract function for this. eg.like

select 
    ex         


        

Answer 1

This is easy to re-implement in PostgreSQL just using SQL functions to tidy up what you've already got:

create function months_of(interval)
 returns int strict immutable language sql as $$
  select extract(years from $1)::int * 12 + extract(month from $1)::int
$$;

create function months_between(date, date)
 returns int strict immutable language sql as $$
   select abs(months_of(age($1, $2)))
$$;

And now select months_between('1978-06-20', '2011-12-09') produces 401.