The results we got are intervals: 1307 days 23:16:00 tells us that the difference between the two timestamps is 1307 days, 23 hours and 16 minutes. This is the result we got in our database (PostgreSQL), but be aware that other databases may return something else (like the number of milliseconds between these two dates, for instance).
The standard of SQL provides two types of intervals. One of them is
INTERVAL 'x-y' YEAR TO MONTH, where x is the number of years and y is the number of months. You can add such an interval to a date/timestamp:
launched + INTERVAL '1-2' YEAR TO MONTH
The above query will add 1 year and 2 months to each launched timestamp in the table
Among popular databases, only MySQL does not support this syntax and has an alternative one:
INTERVAL '1-2' YEAR_MONTH.