April 2024
Intermediate to advanced
800 pages
18h 34m
English
Content preview from SQL All-in-One For Dummies, 4th Edition
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,
O’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.I 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.I’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.I'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.
Chapter 4
Querying Multiple Tables with Relational Operators
IN THIS CHAPTER
Using the UNION statement
Working with the INTERSECT statement
Making exceptions with the EXCEPT statement
Coming together with the JOIN statements
In Chapter 3 of this minibook, I show you how, by using nested queries, data can be drawn from multiple tables to answer a question that involves different ideas. Another way to collect information from multiple tables is to use the relational operators UNION, INTERSECT, EXCEPT, and JOIN. SQL’s UNION, INTERSECT, and EXCEPT operators are modeled after the union, intersect, and except operators of relational algebra. Each one performs a very specific combining operation on the data in two or more tables. The JOIN operator, on the other hand, is considerably more flexible. A number of different joins exist, and each performs a somewhat different operation. Depending on what you want in terms of information retrieved from multiple tables, one or another of the joins or the other relational operators is likely to give it to you. In this chapter, I show you each of ...
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
O’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.
I 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.
I’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.
I'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.