Count months between two timestamp on postgresql?

Question

I want to count the number of months between two dates.

Doing :

SELECT TIMESTAMP \'2012-06-13 10:38:40\' - TIMESTAMP \'2011-04-30 14:38:40\';
         


        

Answer 1

If you will do this multiple times, you could define the following function:

CREATE FUNCTION months_between (t_start timestamp, t_end timestamp)
    RETURNS integer
    AS $$
        SELECT
            (
                12 * extract('years' from a.i) + extract('months' from a.i)
            )::integer
        from (
            values (justify_interval($2 - $1))
        ) as a (i)
    $$
    LANGUAGE SQL
    IMMUTABLE
    RETURNS NULL ON NULL INPUT;

so that you can then just

SELECT months_between('2015-01-01', now());