Adding null and numbers in Oracle

In Oracle, null is added or subtracted from a number, and the result is null,

Therefore, the nvl () function is used for processing.

Declare v_num varchar2 (20); v_num2 varchar2 (20); v_num3 varchar2 (20); v_num4 varchar (20); begin select nvl (null, 0) + 100 into v_num from dual; select null-200 into v_num2 from dual; select 300 + null into v_num3 from dual; select 400-null into v_num4 from dual; dbms_output.put_line (v_num); dbms_output.put_line (v_num2 ); dbms_output.put_line (v_num3); dbms_output.put_line (v_num4); end;