IN THIS PART
Chapter 8: Introducing Basic Query Flow
Chapter 9: Data Types, Expressions, and Scalar Functions
Chapter 10: Merging Data with Joins and Unions
Chapter 11: Including Data with Subqueries and CTEs
Chapter 12: Aggregating Data
Chapter 13: Windowing and Ranking
Chapter 14: Projecting Data Through Views
Chapter 15: Modifying Data
Chapter 16: Modification Obstacles
SQL is like algebra in action.
The etymology of the word "algebra" goes back to the Arabic word "al-jabr," meaning "the reunion of broken parts," or literally, "to set a broken bone." Both algebra and SQL piece together fragments to solve a problem.
I believe select is the most powerful word in all of computer science. Because select is so common, it's easy to take it for granted, but no keyword in any programming language I can think of is as powerful and flexible. Select can retrieve, twist, shape, join, and group data in nearly any way imaginable, and it's easily extended with the insert, update, delete (and now merge!) commands to modify data.
Part II begins by exploring the basic logical query flow and quickly digs deeper into topics such as aggregate queries, relational division, correlated subqueries, and set-difference queries. I've devoted 15 chapters to the select command and its variations because understanding the multiple options and creative techniques available with queries is critical to becoming a successful SQL Server developer, DBA, or architect.
Please don't assume ...