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 statistical functions

MySQL includes some built-in functions for calculating statistics. We covered SUM, AVG, MIN, and MAX earlier in the chapter. Let's learn about a couple of built-in functions that are helpful in calculating statistics.

Learning how to use built-in statistical functions

To calculate standard descriptive statistics, you can use the following built-in functions in addition to the ones previously learned:

  • VARIANCE—This gives you the variance of your data, which calculates what the difference is for each point and the mean of all the points. If zero is returned, then all the data points are the same. A larger value returned means that individual data points are farther from the mean.
  • STDDEV...