SQL学习笔记五去重，给新加字段赋值

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