tl;dr:Anton discusses the "Upsert" operation in SQL, which inserts new records and updates existing ones. The author provides interactive examples and demonstrates how different Database Management Systems handle upserts, including MySQL, SQLite and PostgreSQL.
tl;dr:Anthon provides a look at SQL joins, covering types like "Qualified Join," "Natural Join," "Cross Join," "Partitioned Join," and "Lateral Join." He explains that a "Qualified join" is an umbrella term for the most common types of joins: inner, left, right, and full. "A qualified join connects records from two datasets into one, according to the matching criteria you specify," he states. The article also warns against the use of "Natural Joins," stating they are "almost always a bad idea."