Most of the data you will work with does not start in a CSV file. It lives in databases and behind web services, and getting it out is a core data science skill. This module covers the two main ways in: SQL for querying relational databases, and APIs for pulling data from other systems.
You'll start with relational database basics and the SQL you need to create, read, and filter data. Then you'll move to joins, aggregations, and window functions, which let you answer analytical questions directly in the database. Finally, you'll see how APIs work and how to use them to bring outside data into your projects.
Once you can get data from databases and APIs, you're ready to deal with how messy it usually is in Data Wrangling & Cleaning, the next module in this course.
What a database is, how tables and keys work, and the core of SQL: creating tables, inserting and updating data, basic queries, functions, unions, joins, and nested queries.
A hands-on course on the popular PostgreSQL database: creating tables, CRUD operations, filtering, joins, working with dates, aggregate functions, and constraints.
SQL aimed at data analysis, using BigQuery: writing and running queries, joining tables, and advanced aggregations and window functions.
What an API is and how the web works, then exploring real web APIs such as Spotify and Twilio with Postman and Python, and building a small project that uses one.