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)

Summary

In this chapter, we learned that SQL aggregate functions provide an efficient, flexible way to calculate summary values in SQL query result sets. We discovered that the GROUP BY clause will separate the results of a SELECT query into one or more row groups to support the design and execution of queries with aggregate functions. We saw that the HAVING clause provides a pinpoint way to filter aggregate function calculations. Although they're similar, we learned about the differences between WHERE and HAVING clauses. Finally, we saw that when we use OVER and PARTITION BY in creative ways, MySQL will efficiently expand the range of problems it can solve for us. We can also order the items with a group using the RANK and DENSE RANK functions. In the next chapter, we will look at some advanced features of SQL programming.