oracle初学者求5条sql的语句~~有附加分

Question

Employee(EID, Fname, Lname, Address, DOB, Gender, Salary, Bonus, DID)
Department(DID, Name, Mgr_EID, Mgr_Start_Date)
Project(PID, Name, DID)
Work_On(EID, PID, Hours)
这些是表格，
（9）多少Employee住在London
（10）每个Department中Male和Female的数量
（11）求找到employee中salary的最大值，最小值，平均值
（12）求每个Department中employee的数量和他们的salary的sum
（13）找出那个Department中employee的数量最少？

Answer 1

9、
select count(EID) from Employee where Address='London';
10、
select A.DID,D.Name,A.Male,B.Female from
(select D.DID,sum(Gender) Male from Employee where Gender='Male' group by DID) A,
(select D.DID,sum(Gender) Female from Employee where Gender='Female' group by DID) B,
Department D
where A.IDI=B.DID and B.DID=D.DID;
11、
select max(Salary),min(Salary),avg(Salary) from Employee;
12、
select D.DID,D.Name,sum(E.EID),sum(E.Salary) from
Department D,Employee E where D.DID=E.DID group by D.DID,D.Name;
13、
select * from Department where DID =(select DID from (select DID,sum(EID) as 数量 from Employee group by DID order by 数量) where rownum <=1);

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以上，希望对你有所帮助。

Answer 2

（9）多少Employee住在London
select count(EID) from Employee where Address='London '
（10）每个Department中Male和Female的数量
select count(Gender) from Employee where Gender='Male' group by DID
（11）求找到employee中salary的最大值，最小值，平均值
select max(Salary),min(Salary),avg(Salary) from Employee
（12）求每个Department中employee的数量和他们的salary的sum
select DID,count(employee) ,SUM(salary)from Employee group by DID（13）找出那个Department中employee的数量最少？
SELECT TOP(1) FROM(select DID,count(employee)from Employee group by DID ORDER BY count(employee))