Start From Zero
The SQL Primer
A simple, friendly introduction to relational databases for absolute beginners.
Chapter 1
What is a Database?
A database is a structured collection of data. Unlike a spreadsheet, databases are optimized to handle millions of records securely, validate data consistency, and allow multiple users to read and write information at the exact same time without conflicts.
Chapter 2
Tables, Rows, and Columns
In a relational database, data is stored in grid-like grids called Tables.
- 📁 Columns (Fields): Define the type of data stored (e.g., Name as text, Age as a number).
- 📄 Rows (Records): A single entry in the table (e.g., one specific student's record).
Chapter 3
Introduction to SQL
SQL stands for Structured Query Language. It is the universal language used to speak to relational databases. To ask a database for info, we write a Query.
The most basic query retrieves all columns and records from a table:
SELECT * FROM users;*Note: asterisk (*) means all columns