Book Image

Learn SQL Database Programming

By : Josephine Bush
5 (1)
Book Image

Learn SQL Database Programming

5 (1)
By: Josephine Bush

Overview of this book

SQL is a powerful querying language that's used to store, manipulate, and retrieve data, and it is one of the most popular languages used by developers to query and analyze data efficiently. If you're looking for a comprehensive introduction to SQL, Learn SQL Database Programming will help you to get up to speed with using SQL to streamline your work in no time. Starting with an overview of relational database management systems, this book will show you how to set up and use MySQL Workbench and design a database using practical examples. You'll also discover how to query and manipulate data with SQL programming using MySQL Workbench. As you advance, you’ll create a database, query single and multiple tables, and modify data using SQL querying. This SQL book covers advanced SQL techniques, including aggregate functions, flow control statements, error handling, and subqueries, and helps you process your data to present your findings. Finally, you’ll implement best practices for writing SQL and designing indexes and tables. By the end of this SQL programming book, you’ll have gained the confidence to use SQL queries to retrieve and manipulate data.
Table of Contents (24 chapters)
Section 1: Database Fundamentals
Section 2: Basic SQL Querying
Section 3: Advanced SQL Querying
Section 4: Presenting Your Findings
Section 5: SQL Best Practices

Using the WHERE clause

The WHERE clause helps limit the results of your queries. For example, if you only wanted to see players with more than 40 appearances in games, you can create a WHERE clause to include only those players that meet the criteria.

Understanding how and when to use the WHERE clause to limit query results

The WHERE clause is placed after the FROM clause in a SELECT query. Using the example of players with more than 40 appearances in games, you can execute the following query:

USE lahmansbaseballdb;
SELECT playerid, g_all, g_batting, g_defense FROM appearances
WHERE g_all > 40;

The criterion we are setting in the WHERE clause (for example, g_all > 40) is called an expression. There are different expression...