Book Image

The MySQL Workshop

By : Thomas Pettit, Scott Cosentino
5 (1)
Book Image

The MySQL Workshop

5 (1)
By: Thomas Pettit, Scott Cosentino

Overview of this book

Do you want to learn how to create and maintain databases effectively? Are you looking for simple answers to basic MySQL questions as well as straightforward examples that you can use at work? If so, this workshop is the right choice for you. Designed to build your confidence through hands-on practice, this book uses a simple approach that focuses on the practical, so you can get straight down to business without having to wade through pages and pages of dull, dry theory. As you work through bite-sized exercises and activities, you'll learn how to use different MySQL tools to create a database and manage the data within it. You'll see how to transfer data between a MySQL database and other sources, and use real-world datasets to gain valuable experience of manipulating and gaining insights from data. As you progress, you'll discover how to protect your database by managing user permissions and performing logical backups and restores. If you've already tried to teach yourself SQL, but haven't been able to make the leap from understanding simple queries to working on live projects with a real database management system, The MySQL Workshop will get you on the right track. By the end of this MySQL book, you'll have the knowledge, skills, and confidence to advance your career and tackle your own ambitious projects with MySQL.
Table of Contents (22 chapters)
1
Section 1: Creating Your Database
6
Section 2: Managing Your Database
11
Section 3: Querying Your Database
16
Section 4: Protecting Your Database

Filtering results

Often, the table or tables you are querying have many more rows than you are interested in. Filtering is done in two ways; the first way is only selecting the columns we need. This is what we did in the previous section. The second way is to filter out the rows; this is done with a WHERE clause in the SELECT statement. Besides only returning the data you need, this also allows the database server to use a more efficient way of retrieving the data, which translates to faster queries.

Consider the following query:

SELECT * FROM city WHERE CountryCode='CHE';

This query will return the following results:

Figure 4.4 – The SELECT output, filtered by CountryCode CHE for Switzerland

Here, you return all columns for rows that have CHE as CountryCode. Every row is a city in Switzerland. Now, consider the following example:

SELECT Name, Population FROM country 
WHERE Continent='Oceania' AND Population > 1000000...