Business Modeling- IF Functions, Hypothesis Testing
Excel- Logical Functions in Excel
The video is slightly old but the explanation is clear and the concepts apply to the latest Excel versions.
Statistics- Introduction to Hypothesis Tests
Database Management Systems- Subqueries
A query inside a query is called a sub query. Usually entry level data analysts don't write subqueries at work but some jobs might expect you to have a basic understanding of sub queries- so it does not hurt to learn. For advanced analysts, its definitely a useful skill to have.