Oracle:函数Last,First的用法

创建一个简单的员工信息表

Create Table EmployeeInfo (CODE Number(3) Not Null,EmployeeName varchar2(15),DepartmentID Number(3),Salary NUMBER(7,2),
Constraint PK_EmployeeInfo Primary Key (CODE));

--CODE 编码    --EmployeeName 员工姓名 --DepartmentID 员工所属部门编码 Salary 工资

Select * From EMPLOYEEINFO

SQL语句：

Select DEPARTMENTID,
           Min(SALARY) Keep (DENSE_RANK First Order By SALARY Desc) "FIRST",
           Max(SALARY) Keep (DENSE_RANK Last Order By SALARY Desc) "LAST"
From EMPLOYEEINFO Group By DEPARTMENTID

--此语句的返回结果是每个部门最高的工资和最低的工资：

SQL语句：

Select EmployeeName,DEPARTMENTID,SALARY,
           Min(SALARY) Keep (DENSE_RANK First Order By SALARY Desc) OVER (Partition By DEPARTMENTID)  "FIRST",
           Max(SALARY) Keep (DENSE_RANK Last Order By SALARY Desc) OVER (Partition By DEPARTMENTID) "LAST"
From EMPLOYEEINFO Group By DEPARTMENTID,SALARY,EmployeeName

--此语句返回结果比上述查询更详细，增加了员工姓名：