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SQL学习笔记五去重,给新加字段赋值的方法

数据库操作教程 2022-09-23 20:27:41 转载来源: 网络整理/侵权必删

去掉数据重复增加两个字段alterTABLET_EmployeeAddFSubCompanyVARchar(20);ALTERTABLET_EmployeeADDFDepartmentVARCHAR(20);给新加的字段赋值UPDATET_EmployeeSETFSubCompany='Beijing',FDepartment='Development'whereFNumber='DEV001';UPDATET_EmployeeSETFSubCompany='ShenZhen'

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);

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

标签: SQL 学习 笔记 五去重 新加 字段 赋值 方法


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