SQL学习笔记五去重，给新加字段赋值的方法

去掉数据重复
增加两个字段
alter table t_employee add fsubcompany varchar(20);
alter table t_employee add fdepartment varchar(20);

给新加的字段赋值
update t_employee set fsubcompany='beijing',fdepartment='development' where fnumber='dev001';
update t_employee set fsubcompany='shenzhen',fdepartment='development' where fnumber='dev002';
update t_employee set fsubcompany='beijing',fdepartment='humanresource' where fnumber='hr001';
update t_employee set fsubcompany='beijing',fdepartment='humanresource' where fnumber='hr002';
update t_employee set fsubcompany='beijing',fdepartment='infotech' where fnumber='it001';
update t_employee set fsubcompany='shenzhen',fdepartment='infotech' where fnumber='it002';
update t_employee set fsubcompany='beijing',fdepartment='sales' where fnumber='sales001';
update t_employee set fsubcompany='beijing',fdepartment='sales' where fnumber='sales002';
update t_employee set fsubcompany='shenzhen',fdepartment='sales' where fnumber='sales003';

查询并去重
select distinct fdepartment from t_employee

select distinct fdepartment,fsubcompany from t_employee