Skip to Content
Microsoft® SQL Server® 2008 Bible
book

Microsoft® SQL Server® 2008 Bible

by Paul Nielsen, Mike White, Uttam Parui
August 2009
Beginner to intermediate
1680 pages
42h 30m
English
Wiley
Content preview from Microsoft® SQL Server® 2008 Bible

Chapter 10. Merging Data with Joins and Unions

IN THIS CHAPTER

  • Applying relational algebra

  • Building scalable code with set-based queries

  • Using inner, outer, complex, and Θ (theta) joins

  • Merging data vertically with unions

The introduction to this book stated that my purpose was to share the fun of developing with SQL Server. This chapter is it. Making data twist and shout, pulling an answer out of data with a creative query, replacing a few hundred lines of languishing row-by-row iterative code with a single blazingly fast, set-based SQL query—it's all pure fun and covered here.

Relational databases, by their very nature, segment data into several narrow, but long, tables. Seldom does looking at a single table provide meaningful data. Therefore, merging data from multiple tables is an important task for SQL developers. The theory behind merging data sets is relational algebra, as defined by E. F. Codd in 1970.

Relational algebra consists of eight relational operators:

  • Restrict: Returns the rows that meet a certain criterion

  • Project: Returns selected columns, or calculated data, from a data set

  • Product: Relational multiplication that returns all possible combinations of data between two data sets

  • Union: Relational addition and subtraction that merges two tables vertically by stacking one table above another table and lining up the columns

  • Intersection: Returns the rows common to two data sets

  • Difference: Returns the rows unique to one data set

  • Join: Returns the horizontal merger of two tables, ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.

Read now

Unlock full access

More than 5,000 organizations count on O’Reilly

AirBnbBlueOriginElectronic ArtsHomeDepotNasdaqRakutenTata Consultancy Services

QuotationMarkO’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.
Julian F.
Head of Cybersecurity
QuotationMarkI wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.
Addison B.
Field Engineer
QuotationMarkI’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.
Amir M.
Data Platform Tech Lead
QuotationMarkI'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Mark W.
Embedded Software Engineer

You might also like

Microsoft® SQL Server 2008 R2 Unleashed

Microsoft® SQL Server 2008 R2 Unleashed

Ray Rankins, Paul Bertucci, Chris Gallelli, Alex T. Silverstein
Microsoft® SQL Server 2005 Unleashed

Microsoft® SQL Server 2005 Unleashed

Ray Rankins, Paul Bertucci, Chris Gallelli, Alex T. Silverstein, Tudor Trufinescu, John Kane

Publisher Resources

ISBN: 9780470257043Purchase book