oracle中sum()遇到空字符会怎样？

建表语句：

-- Create table create table CXPS_TEST (   id             NUMBER(19) not null,   create_user_id NUMBER(19),   update_user_id NUMBER(19),   report_type    NUMBER(10) ) tablespace TEST   pctfree 10   initrans 1   maxtrans 255   storage   (     initial 64K     next 1M     minextents 1     maxextents unlimited   ); -- Create/Recreate primary, unique and foreign key constraints  alter table CXPS_TEST   add primary key (ID)   using index    tablespace TEST   pctfree 10   initrans 2   maxtrans 255   storage   (     initial 64K     next 1M     minextents 1     maxextents unlimited   );

原始数据：

select sum(create_user_id),sum(update_user_id),sum(report_type) from CXPS_TEST 

select nvl(sum(create_user_id),0) from CXPS_TEST