SQL is a great, simple to use language to manipulate data within a database. This cheatsheet is aimed at basic SQL for MySQL/MariaDB.
Access on the command line
mysql -u -p When prompted enter your password
Database manipulation
Show databases
SHOW databases;Create new databases
CREATE DATABASE IF NOT EXISTS ; Enter into a database
USE DATABASE ; or just
USE ; Table manipulation
Once you've got a database selected, you can play with tables
Create
Read
Update
Delete
Data manipulation
Most of your SQL life will be CRUDing (Create, Read, Update, Delete) data. So I'll cover the basics here