As part of the SQL journey to explore a database and the data in it, I accessed and built on basic functions of joining tables, grouping data, and using subqueries. Using data from Stack Overflow, Fortune 500 companies, and 311 help requests from Evanston, IL, I first got familiar with numeric, character, and date/time data types. I used functions to aggregate, summarize, and analyze data without leaving the database.
- Join/inner JOIN
- Computing the averages
- Correlation
- Trimming
- Custom aggregation periods
Errors and inconsistencies in the data are common problems, so I developed strategies to clean up messy data. I explored this project using the PostgreSQL database.