A note on SQL and MySQL

This note is based on the learning materials from Liao Xuefeng’s website and W3Schools.

It takes about half a day to quickly learn SQL.

Part One: Basic Concepts

What is SQL? SQL (Structured Query Language) is used to store and manage large amounts of data.

What is MySQL? MySQL is an open-source SQL database management system and search engine.

Key Concepts:

• Foreign Key: Used to establish a many-to-many relationship between tables.
• Primary Key: Used to uniquely identify records in a table (e.g., an ID, GUID, or auto-increment integer type; can also be a composite key).

SQL Relationships:

• One-to-One
• One-to-Many
• Many-to-One
• Many-to-Many

(Above points are referenced from Liao Xuefeng’s SQL Tutorial and GeeksforGeeks).

Part Two: MySQL

• Inner Join: Combines rows from two or more tables based on a related column.
• Left Join: Returns all rows from the left table and the matched rows from the right table.
• UNION: Combines the results of two or more SELECT statements.

Part Three:

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Feel free to complete the third part with the relevant information you have.