What is SQL?

What You'll Learn

• What SQL is
• Key concepts
• Common databases

What is SQL?

SQL (Structured Query Language) is a standard language for managing and manipulating relational databases.

Key Concepts

• Database: Collection of organized data
• Table: Data organized in rows and columns
• Row (Record): Single data entry
• Column (Field): Data attribute
• Primary Key: Unique identifier for each row
• Foreign Key: Reference to another table's primary key

Basic Structure

-- Table structure
CREATE TABLE users (
  id INT PRIMARY KEY,
  name VARCHAR(100),
  email VARCHAR(255) UNIQUE,
  created_at TIMESTAMP
);

-- Data
| id | name  | email           | created_at |
|----|-------|-----------------|------------|
| 1  | John  | john@email.com  | 2024-01-15 |
| 2  | Alice | alice@email.com | 2024-01-16 |

Popular SQL Databases