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)

CROSS JOIN

This type of join is used when you want to combine the elements of a particular column with the elements of another column. This implies that each record from the first table and each record from the second table are laid out in all possible combinations in one single table, just like in the case of a cartesian product. Here is how we can perform this task using the CROSS JOIN syntax:

SELECT [Column List]
  FROM [Table 1] CROSS JOIN [Table 2] 
WHERE [Condition]

To understand this concept well, we will perform CROSS JOIN on simple tables and see how they work in the following exercise.

Exercise 6.04: Implementing CROSS JOINS

Consider that we have a table called Facecards, with a column called suits, and a table called CardSuite with a column called cardvalue. Now, we want to cross-reference all the suits with all the card values. To do this, perform the following steps:

  1. Create a table called Facecards with the following values:
    Create table Facecards...