h520521的博客

–员工表信息 select *from emp; –部门表的所有信息 select from dept; –查询员工表的所有编号，名字，工资 select empno,ename,sal from emp; –查询员工表的编号，名字，工资，年薪 select empno,ename,sal,sal12 from emp; –as别名小名 select empno as 员工编号，ename as ...