I'm glad to help you work through issues or answer questions regarding the data, code, or exercises in Practical SQL. To help me assist you, please answer the following:
What's your operating system (e.g. Windows 10, macOS Mojave, Ubuntu, etc.)?
Did you install PostgreSQL and pgAdmin according to the steps on page xxviii of the book's Introduction? If not, please describe your installation.
Did you download the book's code examples and data from GitHub using the directions on page xxvii of the Introduction? If not, please describe your method.
Chapter, page and code listing number:
Describe the issue or your question. Include any error messages: