Gain insights into relational databases and SQL. Learn about creating, managing, and editing tables using MySQL. Explore complex queries, indexes, and join functions for efficient data handling.

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Relational databases store data in a row-based table structure. Structured Query Language (SQL) is a core language used to retrieve data from the relational database. One of its most widely used extensions, MySQL, also gives you the power to edit, create, and manage the queried data.

In this course, you’ll be introduced to the basics of relational database management with SQL. You’ll use MySQL to create a table, edit the data, and even change the structure. You’ll also create indexes to quickly access data for faster performance on common queries. Additionally, you’ll explore more complex queries to extract useful data with aggregate functions, grouping, ordering, and creating limits and filters in output tables. Finally, you’ll learn how to combine data from different tables with join functions.

By the end of this course, you’ll be able to create, manage, edit, and merge relational databases with confidence. MySQL will prepare you for data projects large and small.

Getting Started with SQL and Relational Databases

# Learning outcome
In this chapter, we learned to query and get useful information. We went over how to combine data from two or more different tables. Combining information wasn’t restricted to information coming from tables only, but it was instead done using subqueries.

We also learned about the aggregate function `sum()` and how it can be used to gain useful insights into our data. We learned about the `join` clause and how we can combine the information that exists in more than one table. We also learned how to attach labels to column headers, make those headers easier to read, and select to display specific columns from a wide result set. Additionally, we counted distinct values in order to get accurate count results.

We gained an understanding of the left join and how we can combine information from two tables even if their rows don’t reference each other. We examined the concept of no value and how it’s represented in SQL, and we learned how to limit the result set to the columns of one table, even if SQL query joins many tables. Finally, we learned how to join information from two different queries.


Get an overview of what we’ve covered in this chapter.


Summary

Get an overview of what we’ve covered in this chapter.

Getting Started

Manage MySQL Server

Basic SQL Commands

Add Columns and Indexes

Count and Sort Records

Foreign Keys

Joins, Left Joins And Subqueries

Conclusion

Summary

Learning outcome