I am a beginner in SQL, I wanted to start a local connection to create a sample database, but cant start one?

I didn't read your question but just to let u know SQL injections are illegal and u CAN do jail time. Last night I tried an SQL injection but I guess there was security or something so I couldn't get in. SQL allows you to change many things on a site. It's high reward but it is ILLEGAL and scary if you get caught.