How do you select all columns, plus the result of a CASE statement in oracle 11g?

Add an alias for mytable like this:

select t.*, (case when PRI_VAL = 1 then 'High'
                when PRI_VAL = 2 then 'Med'
                when PRI_VAL = 3 then 'Low'
          end) as PRIORITY
from MYTABLE t;

This is not dependent on any specific Oracle version, not sure about other databases.