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)

The Not Equal Operator

SQL supports the following symbols to denote the not equal operator: != and <>. The not equal operator will exclude the conditions where values are equal in the results.

Exercise 5.03: Using the != and <> Operators

The store manager realizes that the tomato sauce received has gone bad, so he does not want to present it in the list of available items. To write a query to display all the products except the tomato sauce, perform the following steps:

  1. Enter the SELECT statement, using the WHERE clause and the != operator:
    SELECT ProductName,NetRetailPrice
    FROM Products
    WHERE ProductName != 'tomato sauce'
    ORDER BY NetRetailPrice;
  2. Execute the query; you should see the following results:

    Figure 5.9: List of all products except tomato sauce after using the != operator

  3. As an alternative, now replace the != symbol with the <> operator:
    SELECT ProductName,NetRetailPrice
    FROM Products
    WHERE ProductName <> 'tomato...