Book Image

MySQL 8 Cookbook

By : Karthik Appigatla
Book Image

MySQL 8 Cookbook

By: Karthik Appigatla

Overview of this book

MySQL is one of the most popular and widely used relational databases in the World today. The recently released MySQL 8 version promises to be better and more efficient than ever before. This book contains everything you need to know to be the go-to person in your organization when it comes to MySQL. Starting with a quick installation and configuration of your MySQL instance, the book quickly jumps into the querying aspects of MySQL. It shows you the newest improvements in MySQL 8 and gives you hands-on experience in managing high-transaction and real-time datasets. If you've already worked with MySQL before and are looking to migrate your application to MySQL 8, this book will also show you how to do that. The book also contains recipes on efficient MySQL administration, with tips on effective user management, data recovery, security, database monitoring, performance tuning, troubleshooting, and more. With quick solutions to common and not-so-common problems you might encounter while working with MySQL 8, the book contains practical tips and tricks to give you the edge over others in designing, developing, and administering your database effectively.
Table of Contents (20 chapters)
Title Page
Dedication
Packt Upsell
Contributors
Preface
Index

Views


View is a virtual table based on the result-set of an SQL statement. It will also have rows and columns just like a real table, but few restrictions, which will be discussed later. Views hide the SQL complexity and, more importantly, provide additional security.

 

How to do it...

Suppose you want to give access only to the emp_no and salary columns of the salaries table, and from_date is after 2002-01-01. For this, you can create a view with the SQL that gives the required result.

mysql> CREATE ALGORITHM=UNDEFINED 
DEFINER=`root`@`localhost` 
SQL SECURITY DEFINER VIEW salary_view 
AS 
SELECT emp_no, salary FROM salaries WHERE from_date > '2002-01-01';

Now the salary_view view is created and you can query it just like any other table:

mysql> SELECT emp_no, AVG(salary) as avg FROM salary_view GROUP BY emp_no ORDER BY avg DESC LIMIT 5;

You can see that the view has access to particular rows (that is, from_date > '2002-01-01') and not all of the rows. You can use the view to restrict...