Notes

1..SELECT Employee.E_Name,Street,Salary FROM Employee,Works where Employee.E_Name=Works.E_Name AND Company_Name='C1'

2..SELECT Employee.E_Name FROM Employee,Works,Company WHERE Employee.E_Name=Works.E_Name AND Works.Company_Name=Company.Company_Name AND Employee.City=Company.City

3..SELECT Works.E_Name FROM Works WHERE salary>(SELECT MAX(salary) FROM Works WHERE Company_Name='C2')

SELECT Works.E_Name FROM Works WHERE salary>(SELECT AVG(salary) FROM Works Where Company_Name=)
SELECT Works.E_Name FROM Works AS W1 WHERE salary>(SELECT AVG(salary) FROM Works AS W2 GROUP BY Company_Name HAVING W2.Company_Name=W1.Company_Name)
SELECT Works.E_Name FROM Works W WHERE salary>(SELECT AVG(salary) FROM Works GROUP BY Company_Name) AND Company_Name IN (SELECT Company_Name FROM Works GROUP BY Company_Name)
SELECT Works.E_Name FROM Works W WHERE salary>(SELECT AVG(salary) FROM Works GROUP BY Company_Name HAVING Company_Name=W.Company_Name)
CREATE VIEW test1 AS SELECT Company_Name,Salary FROM Works
4..SELECT Works.E_Name FROM Works WHERE salary>(SELECT AVG(salary) FROM test1 GROUP BY Company_Name HAVING test1.Company_Name=Works.Company_Name)


5..UPDATE Works SET Salary=Salary+5000
SELECT * FROM Works

CREATE TABLE Backup(E_Name varchar(255))
CREATE TRIGGER abc BEFORE UPDATE OF E_NAME ON Employee Referencing OLD AS o AND NEW AS n FOR EACH ROW BEGIN Backup.E_Name=o.Ename;
END;
6..CREATE TRIGGER daabc BEFORE UPDATE OF E_NAME ON Employee
FOR EACH ROW
BEGIN
INSERT INTO Backup values(:old.E_Name);
END;