You can convert character types to numeric types in two ways:

► Explicitly by using TO_NUMBER() function.

► Implicitly by putting character data in a numeric operation.

The sample script below shows you how to convert character types to numeric types:

PROCEDURE proc_convert_1 AS

start_time CHAR(5);

finish_time CHAR(5);

elapsed_time NUMBER(5);

BEGIN

start_time := '12052';

finish_time := '15314';

elapsed_time := TO_NUMBER(finish_time)

- TO_NUMBER(start_time);

elapsed_time := finish_time - start_time; -- same as above

END;