https://github.com/margaretkhendre/employee-analysis-vs-sql-challenge
SQL is used in this repository to examine the hiring process of a fictional company, Pewlett Hackard. Data modeling, data engineering, and a data analysis are displayed here.
https://github.com/margaretkhendre/employee-analysis-vs-sql-challenge
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SQL is used in this repository to examine the hiring process of a fictional company, Pewlett Hackard. Data modeling, data engineering, and a data analysis are displayed here.
- Host: GitHub
- URL: https://github.com/margaretkhendre/employee-analysis-vs-sql-challenge
- Owner: margaretkhendre
- Created: 2023-03-23T00:38:38.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2023-05-11T01:31:45.000Z (about 3 years ago)
- Last Synced: 2025-01-09T09:27:33.330Z (over 1 year ago)
- Topics: sql
- Homepage:
- Size: 7.64 MB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# SQL Challenge
This challenge will display data modeling, data engineering, and data analysis of a fictional company, Pewlett Hackard.
Pewlett Hackard's employee and department files are to be examined to aid their hiring process.
### Data Modeling
QuickDBD has been used to sketch an Entity Relationship Diagram for Pewlett Hackard.
### Data Engineering
Tables have been created for each of the 6 CSV files from Pewlett Hackard in this Table Schema. (Also located in the EmployeeSQL folder.)
Titles
CREATE TABLE TITLES(
Title_ID VARCHAR(20) NOT NULL,
Title VARCHAR(30) NOT NULL,
PRIMARY KEY (Title_ID)
);
SELECT * FROM TITLES
Employees
CREATE TABLE EMPLOYEES(
Emp_no INT NOT NULL PRIMARY KEY,
Emp_title_ID VARCHAR(30) NOT NULL,
Birth_date VARCHAR(20) NOT NULL,
First_name VARCHAR(20) NOT NULL,
Last_name VARCHAR(20) NOT NULL,
Sex VARCHAR(10) NOT NULL,
Hire_date DATE NOT NULL,
FOREIGN KEY (Emp_title_ID) REFERENCES TITLES(Title_ID)
);
SELECT * FROM EMPLOYEES
Departments
CREATE TABLE DEPARTMENTS(
Dept_no VARCHAR(15) NOT NULL,
Dept_name VARCHAR(20) NOT NULL,
PRIMARY KEY (Dept_no)
);
SELECT * FROM DEPARTMENTS
Department Managers
CREATE TABLE DEPT_MANAGER(
Dept_no VARCHAR(15) NOT NULL,
Emp_no INT NOT NULL,
FOREIGN KEY (Emp_no) REFERENCES EMPLOYEES(Emp_no),
FOREIGN KEY (Dept_no) REFERENCES DEPARTMENTS(Dept_no),
PRIMARY KEY (Dept_no, Emp_no)
);
SELECT * FROM DEPT_MANAGER
Department Employees
CREATE TABLE DEPT_EMP(
Emp_no INT NOT NULL,
Dept_no VARCHAR(15) NOT NULL,
FOREIGN KEY (Emp_no) REFERENCES EMPLOYEES(Emp_no),
FOREIGN KEY (Dept_no) REFERENCES DEPARTMENTS(Dept_no),
PRIMARY KEY (Emp_no, Dept_no)
);
SELECT * FROM DEPT_EMP
Salaries
CREATE TABLE SALARIES(
Emp_no INT NOT NULL PRIMARY KEY,
Salary INT NOT NULL,
FOREIGN KEY (Emp_no) REFERENCES EMPLOYEES(Emp_no)
);
SELECT * FROM SALARIES
### Data Analysis
List the employee number, last name, first name, sex, and salary of each employee.
SELECT EMPLOYEES.Emp_no, EMPLOYEES.Last_name, EMPLOYEES.First_name, EMPLOYEES.Sex, SALARIES.Salary
FROM EMPLOYEES
LEFT JOIN SALARIES
ON EMPLOYEES.Emp_no = SALARIES.Emp_no;
List the first name, last name, and hire date for the employees who were hired in 1986.
SELECT First_name, Last_name, Hire_date
FROM EMPLOYEES
WHERE Hire_date LIKE '%1986%'
ORDER BY Hire_date;
List the manager of each department along with their department number, department name, employee number, last name, and first name.
SELECT DEPT_MANAGER.Dept_no, DEPT_MANAGER.Emp_no, DEPARTMENTS.Dept_name, EMPLOYEES.Last_name, EMPLOYEES.First_name
FROM DEPT_MANAGER
JOIN DEPARTMENTS
ON DEPT_MANAGER.Dept_no = DEPARTMENTS.Dept_no
JOIN EMPLOYEES
ON DEPT_MANAGER.Emp_no = EMPLOYEES.Emp_no
ORDER BY Dept_no ASC;
List the department number for each employee along with that employee’s employee number, last name, first name, and department name.
SELECT DEPT_EMP.Dept_no, DEPT_EMP.Emp_no, EMPLOYEES.Last_name, EMPLOYEES.First_name, DEPARTMENTS.Dept_name
FROM DEPT_EMP
JOIN EMPLOYEES
ON DEPT_EMP.Emp_no = EMPLOYEES.Emp_no
JOIN DEPARTMENTS
ON DEPT_EMP.Dept_no = DEPARTMENTS.Dept_no
ORDER BY Dept_no ASC;
List first name, last name, and sex of each employee whose first name is Hercules and whose last name begins with the letter B.
SELECT First_name, Last_name, Sex
FROM EMPLOYEES
WHERE First_name LIKE '%Hercules%' AND Last_name LIKE 'B%'
ORDER BY First_name;
List each employee in the Sales department, including their employee number, last name, and first name.
SELECT DEPT_EMP.Emp_no, EMPLOYEES.Last_name, EMPLOYEES.First_name, DEPARTMENTS.Dept_name
FROM EMPLOYEES
JOIN DEPT_EMP
ON EMPLOYEES.EMP_no = DEPT_EMP.Emp_no
JOIN DEPARTMENTS
ON DEPT_EMP.Dept_no = DEPARTMENTS.Dept_no
WHERE Dept_name LIKE '%Sales%'
ORDER BY Emp_no ASC;
List each employee in the Sales and Development departments, including their employee number, last name, first name, and department name.
SELECT DEPT_EMP.Emp_no, EMPLOYEES.Last_name, EMPLOYEES.First_name, DEPARTMENTS.Dept_name
FROM EMPLOYEES
JOIN DEPT_EMP
ON EMPLOYEES.EMP_no = DEPT_EMP.Emp_no
JOIN DEPARTMENTS
ON DEPT_EMP.Dept_no = DEPARTMENTS.Dept_no
WHERE Dept_name LIKE '%Sales%' OR Dept_name LIKE '%Development%'
ORDER BY Emp_no ASC;
List the frequency counts, in descending order, of all the employee last names (that is, how many employees share each last name).
SELECT Last_name, COUNT(Last_name)
FROM EMPLOYEES
GROUP BY Last_name
ORDER BY COUNT(Last_name) Desc;