SQL选择使用日期时间减去日期时间

Question

I have 2 different fields from a table and both have same format of timestamp.

7/18/2012 10:19:48 AM
and
7/18/2012 10:20:46 AM

How can I subtract two timestamp to get the duration in time.

Answer 1

SELECT (firstDateColumn - secondDateColumn) * 24 * 60 difference_in_minutes
FROM yourtable

If the dates are string then convert them first:

SELECT (TO_DATE(firstDateColumn, 'dd/mm/yyyy HH:MI:SS AM') - 
        TO_DATE(secondDateColumn, 'dd/mm/yyyy HH:MI:SS AM')) * 
        24 * 60 difference_in_minutes
FROM yourtable