Question

Answer the 3 problems below using company sql file

1. Company pays 5% of the salary of an employee as the 401k benefit. List the total amount of money that the company pays as 401k for all of its employees. Change the column name as total401k.
2. Find the total hours that employees work on project ’ProductX’.
3. List the first name, last name, department name, and salary of the female employee that has the highest salary.

below is company.sql

DROP DATABASE IF EXISTS Company;
CREATE DATABASE Company;
use Company;

SET foreign_key_checks = 0;
DROP TABLE IF EXISTS employee;
DROP TABLE IF EXISTS department;
DROP TABLE IF EXISTS dept_locations;
DROP TABLE IF EXISTS project;
DROP TABLE IF EXISTS works_on;
DROP TABLE IF EXISTS dependent;
SET foreign_key_checks = 1;

CREATE TABLE employee (
fname varchar(15) DEFAULT NULL,
minit varchar(1) DEFAULT NULL,
lname varchar(15) DEFAULT NULL,
ssn char(9) NOT NULL,
bdate date DEFAULT NULL,
address varchar(50) DEFAULT NULL,
sex char DEFAULT NULL,
salary decimal(10,2) DEFAULT NULL,
superssn char(9) DEFAULT NULL,
dno int(4) DEFAULT NULL,
PRIMARY KEY (ssn)
);

CREATE TABLE department (
dname varchar(25) DEFAULT NULL,
dnumber int(4) NOT NULL,
mgrssn char(9) DEFAULT NULL,
mgrstartdate date DEFAULT NULL,
PRIMARY KEY (dnumber),
FOREIGN KEY (mgrssn) REFERENCES employee(ssn)
  
);

ALTER TABLE employee ADD (
FOREIGN KEY (dno) REFERENCES department(dnumber),
FOREIGN KEY (superssn) REFERENCES employee(ssn)
);

CREATE TABLE dept_locations (
dnumber int(4) NOT NULL,
dlocation varchar(15) NOT NULL,
PRIMARY KEY (dnumber, dlocation),
FOREIGN KEY (dnumber) REFERENCES department(dnumber)
);

CREATE TABLE project (
pname varchar(25) DEFAULT NULL,
pnumber int(4) NOT NULL,
plocation varchar(15) DEFAULT NULL,
dnum int(4) NOT NULL,
PRIMARY KEY (pnumber),
FOREIGN KEY (dnum) REFERENCES department(dnumber)
);

CREATE TABLE works_on (
essn char(9) NOT NULL,
pno int(4) NOT NULL,
hours decimal(4,1) DEFAULT NULL,
PRIMARY KEY (essn, pno),
FOREIGN KEY (essn) REFERENCES employee(ssn),
FOREIGN KEY (pno) REFERENCES project(pnumber)
);

CREATE TABLE dependent (
essn char(9) NOT NULL,
dependent_name varchar(15) NOT NULL,
sex char DEFAULT NULL,
bdate date DEFAULT NULL,
relationship varchar(8) DEFAULT NULL,
PRIMARY KEY (essn, dependent_name),
FOREIGN KEY (essn) REFERENCES employee(ssn)
);

INSERT INTO employee VALUES
('James','E','Borg','888665555', '1927-11-10','450 Stone, Houston, TX','M',55000,null,null);

INSERT INTO employee VALUES
('Jared','D','James','111111100','1965-05-12','123 Peachtree, Atlanta, GA','M',85000,null,null);
INSERT INTO employee VALUES
('Alex','D','Freed','444444400','1950-09-07','4333 Pillsbury, Milwaukee, WI','M',89000,null,null);
INSERT INTO employee VALUES
('John','C','James','555555500','1975-06-30','7676 Bloomington, Sacramento, CA','M',81000,null,null);
INSERT INTO employee VALUES
('Franklin','T','Wong','333445555','1965-05-15','638 Voss, Houston, TX','M',40000,'888665555',null);
INSERT INTO employee VALUES
('Jennifer','S','Wallace','987654321','1955-12-13','291 Berry, Bellaire, TX','F',43000,'888665555',null);

INSERT INTO department VALUES ('Research', 5, '333445555', '1978-05-22');
INSERT INTO department VALUES ('Administration', 4, '987654321', '1985-01-01');
INSERT INTO department VALUES ('Headquarters', 1, '888665555', '1971-06-19');
INSERT INTO department VALUES ('Software',6,'111111100','1999-05-15');
INSERT INTO department VALUES ('Hardware',7,'444444400','1998-05-15');
INSERT INTO department VALUES ('Sales',8,'555555500','1997-01-01');
--
UPDATE employee SET dno = 5 WHERE ssn = '333445555';
UPDATE employee SET dno = 4 WHERE ssn = '987654321';
UPDATE employee SET dno = 1 WHERE ssn = '888665555';
UPDATE employee SET dno = 6 WHERE ssn = '111111100';
UPDATE employee SET dno = 7 WHERE ssn = '444444400';
UPDATE employee SET dno = 6 WHERE ssn = '555555500';

--
insert into employee values
('Bob','B','Bender','666666600','1984-04-23','8794 Garfield, Chicago, IL','M',96000,null,8);
insert into employee values
('Kim','C','Grace','333333300','1988-12-08','6677 Mills Ave, Sacramento, CA','F',79000,null,6);
insert into employee values
('Evan','E','Wallis','222222200','1990-10-14','134 Pelham, Milwaukee, WI','M',92000,null,7);

INSERT INTO employee VALUES
('John','B','Smith','123456789','1955-01-09','731 Fondren, Houston, TX','M',30000,'333445555',5);
INSERT INTO employee VALUES
('Alicia','J','Zelaya','999887777','1958-07-21','3321 Castle, Spring, TX','F',25000,'987654321',4);
INSERT INTO employee VALUES
('Ramesh','K','Narayan','666884444','1952-09-27','971 Fire Oak, Humble, TX','M',38000,'333445555',5);
INSERT INTO employee VALUES
('Joyce','A','English','453453453','1983-04-26','5631 Rice Oak, Houston, TX','F',25000,'333445555',5);
INSERT INTO employee VALUES
('Ahmad','V','Jabbar','987987987','1979-12-03','980 Dallas, Houston, TX','M',25000,'987654321',4);
insert into employee values
('Jon','C','Jones','111111101','1986-11-04','111 Allgood, Atlanta, GA','M',45000,'111111100',6);
insert into employee values
('Justin',null,'Mark','111111102','1972-08-04','2342 May, Atlanta, GA','M',40000,'111111100',6);
insert into employee values
('Brad','C','Knight','111111103','1988-11-02','176 Main St., Atlanta, GA','M',44000,'111111100',6);

insert into employee values
('Josh','U','Zell','222222201','1986-02-22','266 McGrady, Milwaukee, WI','M',56000,'222222200',7);
insert into employee values
('Andy','C','Vile','222222202','1966-02-10','1967 Jordan, Milwaukee, WI','M',53000,'222222200',7);
insert into employee values
('Tom','G','Brand','222222203','1963-04-12','112 Third St, Milwaukee, WI','M',62500,'222222200',7);
insert into employee values
('Jenny','F','Vos','222222204','1956-07-11','263 Mayberry, Milwaukee, WI','F',61000,'222222201',7);
insert into employee values
('Chris','A','Carter','222222205','1992-08-17','565 Jordan, Milwaukee, WI','F',43000,'222222201',7);

insert into employee values
('Jeff','H','Chase','333333301','1970-05-02','145 Bradbury, Sacramento, CA','M',44000,'333333300',6);
insert into employee values
('Bonnie','S','Bays','444444401','1973-06-05','111 Hollow, Milwaukee, WI','F',70000,'444444400',7);
insert into employee values
('Alec','C','Best','444444402','1987-10-11','233 Solid, Milwaukee, WI','M',60000,'444444400',7);
insert into employee values
('Sam','S','Snedden','444444403','1991-08-12','987 Windy St, Milwaukee, WI','M',48000,'444444400',7);
insert into employee values
('Nandita','K','Ball','555555501','1989-07-22','222 Howard, Sacramento, CA','M',62000,'555555500',6);

insert into employee values
('Jill','J','Jarvis','666666601','1993-10-01','6234 Lincoln, Chicago, IL','F',36000,'666666600',8);
insert into employee values
('Kate','W','King','666666602','1992-07-03','1976 Boone Trace, Chicago, IL','F',44000,'666666600',8);
insert into employee values
('Lyle','G','Leslie','666666603','1982-11-19','417 Hancock Ave, Chicago, IL','M',41000,'666666601',8);
insert into employee values
('Billie','J','King','666666604','1990-10-15','556 Washington, Chicago, IL','F',38000,'666666603',8);
insert into employee values
('Jon','A','Kramer','666666605','1981-10-17','1988 Windy Creek, Seattle, WA','M',41500,'666666603',8);
insert into employee values
('Ray','H','King','666666606','1978-02-24','213 Delk Road, Seattle, WA','M',44500,'666666604',8);
insert into employee values
('Gerald','D','Small','666666607','1976-07-13','122 Ball Street, Dallas, TX','M',29000,'666666602',8);
insert into employee values
('Arnold','A','Head','666666608','1977-12-04','233 Spring St, Dallas, TX','M',33000,'666666602',8);
insert into employee values
('Helga','C','Pataki','666666609','1981-03-15','101 Holyoke St, Dallas, TX','F',32000,'666666602',8);
insert into employee values
('Naveen','B','Drew','666666610','1992-03-14','198 Elm St, Philadelphia, PA','M',34000,'666666607',8);
insert into employee values
('Carl','E','Reedy','666666611','1979-01-10','213 Ball St, Philadelphia, PA','M',32000,'666666610',8);
insert into employee values
('Sammy','G','Hall','666666612','1970-08-01','433 Main Street, Miami, FL','M',37000,'666666611',8);
insert into employee values
('Red','A','Bacher','666666613','1980-05-21','196 Elm Street, Miami, FL','M',33500,'666666612',8);
--

INSERT INTO project VALUES ('ProductX',1,'Bellaire',5);
INSERT INTO project VALUES ('ProductY',2,'Sugarland',5);
INSERT INTO project VALUES ('ProductZ',3,'Houston',5);
INSERT INTO project VALUES ('Computerization',10,'Stafford',4);
INSERT INTO project VALUES ('Reorganization',20,'Houston',1);
INSERT INTO project VALUES ('Newbenefits',30,'Stafford',4);
INSERT INTO project VALUES ('OperatingSystems',61,'Jacksonville',6);
INSERT INTO project VALUES ('DatabaseSystems',62,'Birmingham',6);
INSERT INTO project VALUES ('Middleware',63,'Jackson',6);
INSERT INTO project VALUES ('InkjetPrinters',91,'Phoenix',7);
INSERT INTO project VALUES ('LaserPrinters',92,'LasVegas',7);
--
INSERT INTO dept_locations VALUES (1,'Houston');
INSERT INTO dept_locations VALUES (4,'Stafford');
INSERT INTO dept_locations VALUES (5,'Bellaire');
INSERT INTO dept_locations VALUES (5,'Sugarland');
INSERT INTO dept_locations VALUES (5,'Houston');
INSERT INTO dept_locations VALUES (6,'Atlanta');
INSERT INTO dept_locations VALUES (6,'Sacramento');
INSERT INTO dept_locations VALUES (7,'Milwaukee');
INSERT INTO dept_locations VALUES (8,'Chicago');
INSERT INTO dept_locations VALUES (8,'Dallas');
INSERT INTO dept_locations VALUES (8,'Philadephia');
INSERT INTO dept_locations VALUES (8,'Seattle');
INSERT INTO dept_locations VALUES (8,'Miami');
--
INSERT INTO dependent VALUES ('333445555','Alice','F','1996-03-01-','Daughter');
INSERT INTO dependent VALUES ('333445555','Theodore','M','1993-05-12','Son');
INSERT INTO dependent VALUES ('333445555','Joy','F','1970-08-07','Spouse');
INSERT INTO dependent VALUES ('987654321','Abner','M','1932-02-28','Spouse');
INSERT INTO dependent VALUES ('123456789','Michael','M','1978-01-01','Son');
INSERT INTO dependent VALUES ('123456789','Alice','F', '1978-12-30','Daughter');
INSERT INTO dependent VALUES ('123456789','Elizabeth','F','1957-05-05','Spouse');
INSERT INTO dependent VALUES ('444444400','Johnny','M','1997-04-06','Son');
INSERT INTO dependent VALUES ('444444400','Tommy','M','1999-02-07','Son');
INSERT INTO dependent VALUES ('555555500','Chris','M','1969-04-21','Spouse');
INSERT INTO dependent VALUES ('666884444','Sam','M','1964-03-13','Spouse');
--
INSERT INTO works_on VALUES ('123456789',1, 32.5);
INSERT INTO works_on VALUES ('123456789',2, 7.5);
INSERT INTO works_on VALUES ('666884444',3, 40.0);
INSERT INTO works_on VALUES ('453453453',1, 20.0);
INSERT INTO works_on VALUES ('453453453',2, 20.0);
INSERT INTO works_on VALUES ('333445555',2, 10.0);
INSERT INTO works_on VALUES ('333445555',3, 10.0);
INSERT INTO works_on VALUES ('333445555',10,10.0);
INSERT INTO works_on VALUES ('333445555',20,10.0);
INSERT INTO works_on VALUES ('999887777',30,30.0);
INSERT INTO works_on VALUES ('999887777',10,10.0);
INSERT INTO works_on VALUES ('987987987',10,35.0);
INSERT INTO works_on VALUES ('987987987',30, 5.0);
INSERT INTO works_on VALUES ('987654321',30,20.0);
INSERT INTO works_on VALUES ('987654321',20,15.0);
INSERT INTO works_on VALUES ('888665555',20,null);
INSERT INTO works_on VALUES ('111111100',61,40.0);

Answer 1

SQLs and explanation for each case has been shared below

(1) Total amount of money that the company pays as 401k for all of its employees

We just need to sum all the salaries from employee table and take 5% of it to get the total 401k amount

SELECT
   SUM(salary) * 0.05 AS total401k
FROM
   employee;

Output

(2) Total hours that employees work on project ’ProductX’

We can join the works_on table and project table on project number and take the sum of the hours of the employees working on project 'ProductX'.

SELECT
   SUM(hours)
FROM
   works_on
   INNER JOIN
       project
       ON works_on.pno = project.pnumber
WHERE
   project.pname = 'ProductX';

Output

(3) First name, last name, department name, and salary of the female employee that has the highest salary

First we find the highest salary for a female employee. Then we use this information to get the first name, last name, department name and salary of the female employee with the highest salary.

SELECT
   fname,
   lname,
   dname,
   salary
FROM
   employee
   INNER JOIN
       department
       ON employee.dno = department.dnumber
WHERE
   sex = 'F'
   AND salary =
   (
       SELECT
           MAX(salary)
       FROM
           employee
       WHERE
           sex = 'F'
   );

Output