Book Image

The SQL Workshop

By : Frank Solomon, Prashanth Jayaram, Awni Al Saqqa
Book Image

The SQL Workshop

By: Frank Solomon, Prashanth Jayaram, Awni Al Saqqa

Overview of this book

Many software applications are backed by powerful relational database systems, meaning that the skills to be able to maintain a SQL database and reliably retrieve data are in high demand. With its simple syntax and effective data manipulation capabilities, SQL enables you to manage relational databases with ease. The SQL Workshop will help you progress from basic to advanced-level SQL queries in order to create and manage databases successfully. This Workshop begins with an introduction to basic CRUD commands and gives you an overview of the different data types in SQL. You'll use commands for narrowing down the search results within a database and learn about data retrieval from single and multiple tables in a single query. As you advance, you'll use aggregate functions to perform calculations on a set of values, and implement process automation using stored procedures, functions, and triggers. Finally, you'll secure your database against potential threats and use access control to keep your data safe. Throughout this Workshop, you'll use your skills on a realistic database for an online shop, preparing you for solving data problems in the real world. By the end of this book, you'll have built the knowledge, skills and confidence to creatively solve real-world data problems with SQL.
Table of Contents (13 chapters)

Case Statements

As we build SQL queries and statements, often, we'll need a way to examine a set of conditions and then return a value based on one of those conditions. The MySQL and SQL Server CASE statement does exactly this. For example, we may need a SELECT query column that shows different values based on different, specific values or conditions that have been found in a specific database table column. We'll see an illustration of this in the next paragraph. A SQL CASE statement will step through a list of conditions and then return a result based on the first matching condition it finds. The CASE statements work in the SELECT, UPDATE, DELETE, WHERE, and HAVING clauses, and they operate a lot like simple IF…ELSE statements. Note that the CASE statement can't control execution flow in a SQL function or stored procedure. We'll look at functions and stored procedures in more detail later.

We can get basic product information from the Products table,...