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

# Show existing customers
First, let’s see the current `customers` table again. 




Now, let’s execute the following command. This will try to create a new customer, `John Boo`, but with the `identity` value equal to the `identity` of an existing customer (that of `John Woo`).


insert into customers(name, identity) values ('John Boo','JW0001');

We're doing a business error on purpose here. We’ve inserted the new customer with the wrong identity. However, the query has been successfully executed, and the new customer has been inserted without any warning or error. So, we get the `Succeeded` response.


Getting Started

Manage MySQL Server

Basic SQL Commands

Add Columns and Indexes

Count and Sort Records

Foreign Keys

Joins, Left Joins And Subqueries

Conclusion

Unique Indexes

Show existing customers