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

# Overview of indexes
Searching for a particular customer inside a table that has two customers is quick. The response is returned within 0.00 seconds. Is the response equally fast when a table has two million customers, though? No way. When we issue the `select` statement, for example, MySQL will scan the whole table. It starts from the first row and takes all the rows one by one until it matches the row with the required `identity` value. This is very slow when a table has a lot of rows. Even with only a few thousand rows, such queries will experience delays in returning the results.

To speed up the response of these queries, we need to use indexes. An **index** is a tool that will help us search. MySQL uses the index in the background to retrieve data quickly.

An index in MySQL is like the index at the end of a book. It has terms and the pages where the term can be found, which helps the reader quickly locate the page that references a term.



Getting Started

Manage MySQL Server

Basic SQL Commands

Add Columns and Indexes

Count and Sort Records

Foreign Keys

Joins, Left Joins And Subqueries

Conclusion

Indexes

Overview of indexes