如何在我的結果中列出另一個表中的部門名稱？

Question

以下是我的員工表：

create table EMPLOYEES 
    (EmpID char(4)   unique Not null, 
    Ename varchar(10), 
    Job  varchar(9), 
    MGR  char(4), 
    Hiredate date, 
    Salary decimal(7,2), 
    Comm  decimal(7,2), 
    DeptNo char(2)   not null, 
     Primary key(EmpID), 
     Foreign key(DeptNo) REFERENCES DEPARTMENTS(DeptNo)); 


insert into EMPLOYEES values (7839,'King','President',null,'17-Nov-11',5000,null,10); 
insert into EMPLOYEES values (7698,'Blake','Manager',7839,'01-May-11',2850,null,30); 
insert into EMPLOYEES values (7782,'Clark','Manager',7839,'02-Jun-11',2450,null,10); 
insert into EMPLOYEES values (7566,'Jones','Manager',7839,'02-Apr-11',2975,null,20); 
insert into EMPLOYEES values (7654,'Martin','Salesman',7698,'28-Feb-12',1250,1400,30); 
insert into EMPLOYEES values (7499,'Allen','Salesman',7698,'20-Feb-11',1600,300,30); 
insert into EMPLOYEES values (7844,'Turner','Salesman',7698,'08-Sep-11',1500,0,30); 
insert into EMPLOYEES values (7900,'James','Clerk',7698,'22-Feb-12',950,null,30); 
insert into EMPLOYEES values (7521,'Ward','Salesman',7698,'22-Feb-12',1250,500,30); 
insert into EMPLOYEES values (7902,'Ford','Analyst',7566,'03-Dec-11',3000,null,20); 
insert into EMPLOYEES values (7369,'Smith','Clerk',7902,'17-Dec-10',800,null,20); 
insert into EMPLOYEES values (7788,'Scott','Analyst',7566,'09-Dec-12',3000,null,20); 
insert into EMPLOYEES values (7876,'Adams','Clerk',7788,'12-Jan-10',1100,null,20); 
insert into EMPLOYEES values (7934,'Miller','Clerk',7782,'23-Jan-12',1300,null,10); 

以下是我的DEPARTMENTS表：

create table DEPARTMENTS 
(DeptNo char(2) unique Not null, 
DName varchar(14), 
Location varchar(13), 
Primary key(DeptNo)); 

insert into DEPARTMENTS values (10,'Accounting','New York'); 
insert into DEPARTMENTS values (20,'Research','Dallas'); 
insert into DEPARTMENTS Values (30,'Sales','Chicago'); 
insert into DEPARTMENTS values (40,'Operations','Boston'); 

以下是我的查詢：

select ename, salary 
from EMPLOYEES 
where Salary > 
(select AVG(salary) 
from EMPLOYEES); 

的Sql小提琴演示：http://www.sqlfiddle.com/#!3/61ca4/1

Answer 1

select e.ename, 
     e.salary, 
     d.DName 
    from EMPLOYEES as e 
     inner join DEPARTMENTS as d on e.DeptNo = d.DeptNo 
where e.Salary > (select AVG(salary) from EMPLOYEES); 

的Sql小提琴演示：http://www.sqlfiddle.com/#!3/61ca4/2

Answer 2

select E.ename, E.salary, D.DName 

from Employees E, Departments D 

where E.Deptno = D.Deptno 

And Salary > (select AVG(salary) from EMPLOYEES);