How do I convert an interval into a number of hours with postgres?

Question

Say I have an interval like

4 days 10:00:00

in postgres. How do I convert that to a number of hours (106 in this case?) Is there a function

Answer 1

If you convert table field:

1. Define the field so it contains seconds:

    CREATE TABLE IF NOT EXISTS test (
        ...
        field        INTERVAL SECOND(0)
    );
   

2. Extract the value. Remember to cast to int other wise you can get an unpleasant surprise once the intervals are big:

   EXTRACT(EPOCH FROM field)::int