Basic SQL

SQL Joins

SQL Aggregations

SQL Subqueries & Temporary Tables

SQL Window Functions

SQL Advanced JOINS & Performance Tuning

Create a Git Repo

Review A Repo’s History

Add Commits to A Repo

Tagging, Branching, and Merging

Undoing Changes

Working With Remotes

Staying In Sync With A Remote Repository

01. Video: Introduction

What this lesson is about…

Up to this point you have learned a lot about working with data using SQL. This lesson will focus on three topics:

  1. Subqueries
  2. Table Expressions
  3. Persistent Derived Tables

Both subqueries and table expressions are methods for being able to write a query that creates a table, and then write a query that interacts with this newly created table. Sometimes the question you are trying to answer doesn’t have an answer when working directly with existing tables in database.

However, if we were able to create new tables from the existing tables, we know we could query these new tables to answer our question. This is where the queries of this lesson come to the rescue.

If you can’t yet think of a question that might require such a query, don’t worry because you are about to see a whole bunch of them!