Relational Algebra Specify the following queries on the COMPANY relational database schema shown in Figure 3.5, using the relational operators discussed in this chapter. Also, show the result of each query.- List the managers who are controlling more than 2 projects. - List the names of employees all of whose dependents were born before 1990. - Retrieve the average salary of employees who work totally no less than 30 hours on projects. ΕMPLOYΕΕSex Salary Super_ssn Dno30000 33344555540000 888665555FnameMinitLnameSsnBdateAddress123456789 1965-01-09 731 Fondren, Houston, TX M333445555 1955-12-08 638 Voss, Houston, TX999887777 1968-01-19 3321 Castle, Spring, TXJohnBSmith5FranklinWongMFWallace 987654321 1941-06-20 291 Berry, Bellaire, TXNarayan 666884444 1962-09-15975 Fire Oak, Humble, TX MEnglish 453453453 1972-07-31 5631 Rice, Houston, TX987987987 1969-03-29 980 Dallas, Houston, TX888665555 1937-11-10 450 Stone, Houston, TXAliciaZelaya25000 9876543214Jennifer43000 8886655554RameshK38000 3334455555F 25000 333445555M 25000 987654321M 55000 NULLJoyceAAhmadVJabbar4E BorgJamesDEPT LOCATIONSDEPARTMENTDnameDnumberMgr_ssnMgr_start_dateDnumberDlocationResearch3334455551988-05-22HoustonAdministration4Stafford49876543211995-01-01Headquarters18886655551981-06-19BellaireSugarlandHoustonWORKS ONPROJECTEssnPnoHoursPnamePnumberPlocationDnum12345678932.5ProductXBellaire123456789ProductYSugarland7.525666884444340.0Productz3Houston5453453453120.0Computerization10Stafford4ReorganizationNewbenefits45345345320.020Houston1333445555210.030Stafford4333445555320.03334455551010.0DEPENDENT3334455552010.0Relationship1986-04-05| DaughterEssnDependent_nameSexBdate9998877773030.0333445555AliceF9998877771010.0333445555TheodoreM1983-10-25Son9879879871035.0333445555Joy1958-05-03Spouse987987987305.0AbnerSpouse9876543211942-02-289876543213020.0123456789MichaelM1988-01-04Son9876543212015.0123456789Alice1988-12-30Daughter88866555520NULL123456789ElizabethF1967-05-05Spouse

Here are the SQL queries as asked: 1. List the department managers who are controlling more than 2 projects. select e.Fname,e.Lname,e.Ssn from EMPLOYEE e, DEPARTMENT d, Project p where e.Ssn = d.Mgr_ssn and d.Dnumber = p.Dnum group by (e.Fname,e.Lname,e.Ssn ) having count(*) > 2; 2. Retrieve the names of the departments that only located in ‘Houston’. select d.Dname from DEPARTMENT d, DEPT_LOCATIONS dl where d.Dnumber = dl.Dnumber and dl.Dlocation = 'Houston' and dl.Dnumber in (select Dnumber from DEPT_LOCATIONS group by (Dnumber) having count(Dnumber) = 1 ); 3. List the names of employees all of whose dependents were born before 1960. select e.Fname, e.Lname from EMPLOYEE e, DEPENDENT d where e.Ssn = d.Essn and extract(YEAR from d.Bdate) < 1960; 4. List the names of departments managed by the direct subordinate of the manager of ‘Headquarters’ department. select d.Dname from DEPARTMENT d, EMPLOYEE e where d.Dnumber = e.Dno and d.Dname = 'Headquarters' and e.Super_ssn =null;