SQL is used to communicate with databases in order to manipulate & retrieve data.

WHY LEARN?

• Many applications use databases to store & change data
• Tons of businesses use relational databases
• Useful for personal projects
• Great technical skill you can add to your resume

QUICK FACTS

• SQL has many extensions/versions created by others (MySQL, PostgreSQL, MariaDB, Oracle DB, etc.)
• First developed by IBM researchers (’70s), then developed & publicly released by Oracle (’79)
• In 3rd place for Most Popular Technologies on StackOverflow

QUICK EXAMPLE

Say you are connected to your database and you have several tables with one of them named, “cars”. The cars table has 4 fields: id, make, model, and year. For whatever reason, your application wants id, make, and model. Your query would look something like this.

CREATE DATABASE

Previously, we assumed we were connected to a database and that it had a cars table. What if neither existed? Let’s CREATE the database first since tables are stored in them. We can SHOW the available database by running : It’s that simple! Before we proceed to creating a table for testdb, we must run this command : The commands we run next will apply to this database, unless we specifically USE a different database.

CREATE TABLE

We now have a database, but we are missing the cars table. Let’s CREATE the table.

INSERT DATA

Now let’s insert the rows of data.

TRUNCATE TABLE

To remove all the rows of data in the table, but preserve the table, we would TRUNCATE it.

DROP TABLE

To remove the table from the database, we would DROP the table.

RESOURCES

To learn more, I highly recommend visiting these sites:

• freecodecamp.org
• tutorialspoint.org
• khanacademy.org
• Sqlbolt.com

On a personal note, I’ve learned MySQL first and my experience with it was great! It doesn’t matter which version of SQL you learn, what matters is learning it! Start a project or include it in one of your existing projects.

THANK YOU

Follow @codeherk for tips on Software Development.

Questions? Comments? Requests?

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