Beginning SQL Queries
Beginning SQL Queries From Novice to Professional
You will learn about joins, intersections, unions, differences, selection of rows, and projection of columns. You will see how to implement these ideas in different ways using simple and nested queries, and you will be introduced to a variety of techniques for aggregating and summarizing data, including the use of window functions.
You will also learn how you can investigate and improve the efficiency of your queries. Most important of all, you will learn different ways to get started on a troublesome problem.