Leetcode Database，leetcodedatabase

Leetcode Database，leetcodedatabase

用oracle分析函數實現的 Leetcode Database 題

第一題：Department Top Three Salaries 

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

附：建表及資料準備

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');

第二題：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： 建表及資料準備

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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