-- Cartesian Product : Product Join without Where Clause

select * from employee, department;

select COUNT(*) from employee, department;

-- Selection with Join Condition select *

from Employee e, Department d

where e.dno = d.dnumber;

select e.fname, e.lname, e.dno, d.dname

from Employee e, Department d

where d.dname = 'research' and e.dno = d.dnumber;

-- Selection with Join Condition

select * from Employee e, Department d

where e.dno = d.dnumber;

--Projection Columns only

select e.fname, e.lname, e.dno, d.dname

from Employee e, Department d

where d.dname = 'research' and e.dno = d.dnumber;

--Self Join: Find all the Supervisor’s First names and Last Names

select S.Ssn, S.Fname, S.Lname, S.Dno

from Employee E, Employee S

where E.Super_ssn = S.Ssn;

--Self Join: Find Last name of Smith’s Supervisor

select S.Ssn, S.Fname, S.Lname, S.Dno from Employee E, Employee S

where E.Lname = 'Smith' and E.Super_ssn = S.Ssn;