Data Analysis - SQL

Employee Database

• This is a research project on employees of the corporation from the 1980s and 1990s. All that remains of the database of employees from that period are six CSV files.

Tasks

• Design and create the employee’s database
• Import the CSV's into the tables
• Perform the data analysis

ER diagram

Data

• Create the Employee database into PostgreSQL.
• Upload the data from six CSV files into the database.

Data Analysis

• Database is up and running and the following analyses were done:

1. List the following details of each employee: employee number, last name, first name, sex, and salary.

2. List first name, last name, and hire date for employees who were hired in 1986.

3. List the manager of each department with the following information: department number, department name, the manager's employee number, last name, first name.

4. List the department of each employee with the following information: employee number, last name, first name, and department name.

5. List first name, last name, and sex for employees whose first name is "Hercules" and last names begin with "B."

6. List all employees in the Sales department, including their employee number, last name, first name, and department name.

7. List all employees in the Sales and Development departments, including their employee number, last name, first name, and department name.

8. In descending order, list the frequency count of employee last names, i.e., how many employees share each last name.

Analysis with Graphs

Histogram to visualize the most common salary ranges for employees.

Bar Chart to visualize the average salary by title.

Tools

• PostgreSQL, Jupyter Notebook, Python, SQLAlchemy, Pandas, Pyplot