Ch. 4 Relational Algebra (2) Exercises

Algebra (3) 데이터베이스시스템 2 Queries in Ch.4 (p.161, p.166) EMPLOYEE (p.161) EmpNoEmpNameTitleManagerSalaryDNO 2106 김창섭대리 10032,500, 박영권과장 43773,000, 이수민부장 43774,000, 조민희과장 43773,000, 최종철사원 30111,500, 김상원사원 34261,500, 이성래사장 5,000,0002 DEPARTMENT (p.166) DeptNoDeptNameFloor 1 영업 8 2 기획 10 3 개발 9 4 총무 7

Algebra (3) 데이터베이스시스템 3 Queries in Ch.4 (p.161, p.166) EMPL (EmpNo, EmpName, Title, Manager, Salary, DNO) (p.161) DEPT (DeptNo, DeptName, Floor) (p.166) Q (p.160) List all the information of employees who work for the department numbered 3 EMPL where DNO = 3 Q (p.162) List all the titles of employees. EMPL [Title]

Algebra (3) 데이터베이스시스템 4 EMPL (EmpNo, EmpName, Title, Manager, Salary, DNO) DEPT (DeptNo, DeptName, Floor) Q (p.164) List DeptNo of the department for which ' 김창섭 ' works or that of the department ' 개발 ' (EMPL where EmpName= ' 김창섭 ') [DNO] Union (DEPT where DeptName= ' 개발 ') [DeptNo] Q (p.165) List DeptNos of departments for which ' 김창섭 ' or ' 최종철 ' works and that of the department ' 기획 ' (EMPL where EmpName = ' 김창섭 ' or EmpName= ' 최종철 ') [DNO] Intersect (DEPT where DeptName= ' 기획 ') [DeptNo]

Algebra (3) 데이터베이스시스템 5 EMPL (EmpNo, EmpName, Title, Manager, Salary, DNO) DEPT (DeptNo, DeptName, Floor) Q (p.166) List DeptNos of departments without any employees in it. DEPT [DeptNo] – EMPL [DNO] Q (p.168) Get the Cartesian product of EMPL and DEPT. EMPL X DEPT (degree: 9, cardinality: 28) Q (p.169) Get the equi-Join of Employee relation and Department relation (EMPL X DEPT) where DNO = DeptNo

Algebra (3) 데이터베이스시스템 6 EMPL (EmpNo, EmpName, Title, Manager, Salary, DNO) DEPT (DeptNo, DeptName, Floor) Q (p.171) Get the natural join of EMPL and DEPT (EMPL rename DNO as DeptNo) join DEPT (degree: 8, cardinality: 7) Q (p.172) List the names and salaries of employees who work for departments of DeptNo 2 or 3. (EMPL where DNO=2 or DNO=3) [EmpName, Salary] Q (p.173) List the names of employees who work for the department ' 개발 ' ( (EMPL rename DNO as DeptNo) join (DEPT where DeptName= ' 개발 ') ) [EmpName]

Algebra (3) 데이터베이스시스템 7 EMPL (EmpNo, EmpName, Title, Manager, Salary, DNO) DEPT (DeptNo, DeptName, Floor) 집단함수 : SUM, AVG, MAX, MIN, COUNT (p.174) Q (p.174) Get the average salary of all the employees summarize EMPL per{ } add Avg(Salary) (degree: 1, cardinality: 1) summarize EMPL per{ } add Avg(Salary) as Avg_Sal Q (p.175) List the average salary of the employees for each department. summarize EMPL per{DNO} add Avg(Salary) as Avg_Sal (degree: 2, cardinality: #of departments=3)

Algebra (3) 데이터베이스시스템 8

Algebra (3) 데이터베이스시스템 9 Query set A (pp.526–534) EMPL (EmpNo, EmpName, Title, Manager,Salary, HireDate, DNO) DEPT (DeptNo, DeptName, Floor) Q1 : List the department names and DeptNos of all the departments. DEPT [DeptName, DeptNo] Q2 : Get all the detail of EMPL relation EMPL Q4 : List names and titles of employees who work for the department with number 3. (EMPL where DNO=3) [EmpName, Title]

Algebra (3) 데이터베이스시스템 10 Query set A (pp.526–534) EMPL (EmpNo, EmpName, Title, Manager, Salary, HireDate, DNO) DEPT (DeptNo, DeptName, Floor) Q6 : List names and HireDates of employees who joined the company since Feb. 1, (EMPL where HireDate >= ‘ ’) [EmpName, HireDate] Q7 : Get all the names and titles of employees who are not ' 과장 ' (EMPL where Title <> ' 과장 ') [EmpName, Title] Q9 : List names, titles, and salaries of employees whose salaries are between 2,000,000 and 3,000,000 (EMPL where Salary>= and Salary <= ) [EmpName, Title, Salary]

Algebra (3) 데이터베이스시스템 11 Query set A (pp.526–534) EMPL (EmpNo, EmpName, Title, Manager, Salary, HireDate, DNO) DEPT (DeptNo, DeptName, Floor) Q12 : List names, titles, and DNO’s of employees who work for department 2 as either a ' 대리 ' or a ‘ 과장 '. (EMPL where DNO=2 and (Title= ‘ 대리 ' or Title= ' 과장 ') ) [EmpName, Title, DNO] Q13 : Get all names and titles of employees whose name starts with ' 김 ' (EMPL where EmpName like ' 김 %’) [EmpName, Title] Q14 : Get the name and the title of the highest manager (EMPL where Manager is NULL) [EmpName, Title] Q15, Q16, Q17: EMPL [EmpName, Title]

Algebra (3) 데이터베이스시스템 12 Query set A (pp.526–534) EMPL (EmpNo, EmpName, Title, Manager, Salary, HireDate, DNO) DEPT (DeptNo, DeptName, Floor) Q18 : Get the number of employees who work in the department 3 and their average salary summarize (EMPL where DNO=3) per{ } add (Count(*) as Num_Emp, Avg(Salary) as Avg_Sal) Q20 : List names and Titles of employees who work in the department ' 개발 ' ( (EMPL rename DNO as DeptNo) join (DEPT where DeptName= ' 개발 ') ) [EmpName, Title]

Algebra (3) 데이터베이스시스템 13 Query set A (pp.526–534) EMPL (EmpNo, EmpName, Title, Manager, Salary, HireDate, DNO) DEPT (DeptNo, DeptName, Floor) Q23 : Get the names of employees who earn more than the average salary of all the employees ( (EMPL X (summarize EMPL per{ } add Avg(Salary) as Avg_Sal) ) where Salary > Avg_Sal) [EmpName] Q27 : List the DeptNo, department_names, and floors of the departments in which nobody works (DEPT[DeptNo] – (EMPL rename DNO as DeptNo) ) Join DEPT DEPT – (DEPT join (EMPL rename DNO as DeptNo) ) [DeptNo, DeptName, Floor]

Algebra (3) 데이터베이스시스템 14