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.

testmysql.tar.gz

sql spa

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


In this chapter, we’ll learn about the `join` clause and how we can combine information that exists in more than one table. We can attach labels to column headers to make those headers easier to read. We’ll select to display specific columns from a wide result set and  count distinct values to get accurate count results. We’ll also learn about the left join and how we can combine information from two tables even if rows on the first table don’t reference rows on the second.



We’ll get into the concept of no value and how it’s represented in SQL. We’ll also limit the result set to the columns of one table even if the SQL query joins many tables. We’ll display a dynamically evaluated column and, finally, learn about the sum() aggregate function and `group by` clause.


# Schema of `customers_db`
Let’s review the database schema of our `customers_db` database again.


Learn the basics of joins and subqueries.

Getting Started

Manage MySQL Server

Basic SQL Commands

Add Columns and Indexes

Count and Sort Records

Foreign Keys

Joins, Left Joins And Subqueries

Conclusion

Introduction to Joins