Leetcode Database，leetcodedatabase

Leetcode Database，leetcodedatabase

用oracle分析函数实现的 Leetcode Database 题

第一题：Department Top Three Salaries 

select a.depart, a.name, a.salary
from (
select d.name depart, e.name name, rank()over(partition by d.id order by e.salary desc) rank, e.salary salary
from department d, employee e
where d.id=e.departmentid
) a
where a.rank<=3;

附：建表及数据准备

DROP TABLE Employee PURGE;
CREATE TABLE Employee (      Id INT PRIMARY KEY,     Name CHAR(20), Salary INT, DepartmentId INT );
INSERT INTO Employee(Id, Name,Salary,DepartmentId) VALUES(1,'joe',70000,1);
INSERT INTO Employee(Id, Name,Salary,DepartmentId) VALUES(2,'henry',80000,2);
INSERT INTO Employee(Id, Name,Salary,DepartmentId) VALUES(3,'sam',60000,2);
INSERT INTO Employee(Id, Name,Salary,DepartmentId) VALUES(4,'Max',90000,1);
INSERT INTO Employee(Id, Name,Salary,DepartmentId) VALUES(5,'Janet',69000,1);
INSERT INTO Employee(Id, Name,Salary,DepartmentId) VALUES(6,'Randy',85000,1);
INSERT INTO Employee(Id, Name,Salary,DepartmentId) VALUES(7,'rap',85000,1);

DROP TABLE  Department PURGE; 
CREATE TABLE Department ( Id INT PRIMARY KEY, Name CHAR(20) );
INSERT INTO Department(Id, Name) VALUES(1,'IT');
INSERT INTO Department(Id, Name) VALUES(2,'Sales');

第二题：Rank Scores 

Write a SQL query to rank scores. If there is a tie between two scores, both should have the same ranking. 

Note that after a tie, the next ranking number should be the next consecutive integer value. 

In other words, there should be no "holes" between rank

select score, dense_rank()over(order by score desc)
from Scores ;

附： 建表及数据准备

DROP TABLE Scores PURGE;
CREATE TABLE Scores
(
    Id INT PRIMARY KEY,
    Score FLOAT
);
INSERT INTO Scores(Id, Score) VALUES(1,3.59);
INSERT INTO Scores(Id, Score) VALUES(2,3.65);
INSERT INTO Scores(Id, Score) VALUES(3,4.00);
INSERT INTO Scores(Id, Score) VALUES(4,3.85);
INSERT INTO Scores(Id, Score) VALUES(5,4.00);
INSERT INTO Scores(Id, Score) VALUES(6,3.65);

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