1、创建测试表，
create table test_null(work_no VARCHAR(20), chinese_name varchar2(20), department_name varchar2(20), department_id varchar2(20), fee varchar2(20));
2、插入测试数据
insert into test_null values(null,null,null,null,'5.00');
insert into test_null values(null,null,null,null,'17.00');
insert into test_null values(null,null,null,null,'29.50');
insert into test_null values(null,null,null,null,'52.00');
insert into test_null values(321269,'梁XX','外销','WX','5.00');
3、查询原始表的记录，select t.*, rowid from test_null t ，有很多字段值为空的记录，
4、编写sql，限定条件，过滤掉字段为null的记录，
select t.*
from test_null t
where work_no is not null
and chinese_name is not null
and department_name is not null
and department_id is not null，
