The minutes_between() function determines the truncated number of full minutes between two timestamps.
bigint = minutes_between(timestamp t1, timestamp t2);
The t1 value specifies the beginning timestamp.
The t2 value specifies the ending timestamp.
select minutes_between('1996-02-27 06:12:33' , '1996-02-27 07:12:00');
MINUTES_BETWEEN
-----------------
59
(1 row)