CREATE TABLE staff (
    Id varchar(10) PRIMARY KEY,
    Name varchar(255) NOT NULL,
    Department varchar(10) CHECK (Department IN ('SALES', 'ACCOUNT', 'HR')),
    Salary int CHECK (Salary > 15000),
    Location varchar(10)
);
INSERT INTO staff (Id, Name, Department, Salary, Location)
VALUES 
('S1', 'Amit', 'SALES', 20000, 'KOL'),
('S2', 'Binay', 'SALES', 20000, 'DEL'),
('H1', 'Anil', 'HR', 30000, 'KOL'),
('H2', 'Anil', 'HR', 35000, 'KOL'),
('S3', 'Asmit', 'SALES', 25000, 'KOL'),
('A1', 'Arun', 'ACCOUNT', 28000, 'DEL'),
('A2', 'Arjun', 'ACCOUNT', 40000, 'DEL');

SELECT * FROM staff WHERE Department = 'SALES';
SELECT Name, Id FROM staff;
SELECT Name, Id, Salary FROM staff WHERE Department = 'ACCOUNT';
SELECT Name, Id FROM staff WHERE Location = 'KOL' AND Salary > 25000;
UPDATE staff SET Location = 'CHN' WHERE Location = 'DEL';
SELECT Location, SUM(Salary) FROM staff GROUP BY Location;
SELECT MAX(Salary) FROM staff WHERE Location = 'KOL';
SELECT * FROM staff WHERE Name LIKE 'A%';
SELECT * FROM staff WHERE Salary = (SELECT MAX(Salary) FROM staff);
SELECT * FROM staff WHERE LENGTH(Department) = 2;

SELECT * FROM staff WHERE Salary = (
    SELECT MAX(Salary) FROM staff WHERE Salary < (SELECT MAX(Salary) FROM staff)
);