You have two options:
Refer to the exception directly by number:
BEGIN
EXECUTE IMMEDIATE 'CREATE SEQUENCE S_TEST START WITH 1 INCREMENT BY 1';
EXCEPTION
WHEN OTHERS THEN
IF SQLCODE = -955 THEN
NULL; -- suppresses ORA-00955 exception
ELSE
RAISE;
END IF;
END;
Other option is to use EXCEPTION_INIT
Pragma directive to bind a known Oracle error number to user defined exception;
DECLARE
name_in_use exception; --declare a user defined exception
pragma exception_init( name_in_use, -955 ); --bind the error code to the above
BEGIN
EXECUTE IMMEDIATE 'CREATE SEQUENCE S_TEST START WITH 1 INCREMENT BY 1';
EXCEPTION
when name_in_use then
null; --suppress ORA-00955 exception
END;
BTW Is there any syntax to catch errors by just providing the error-codes?
Yes, I've demonstrated it in the first example
Further reading for variations on this: