SQL

Introduction to SQL

SQL (Structured Query Language) is how you read and write data stored in a relational database. Data lives in tables, think of a table like a spreadsheet, with named columns and one row per record.

Example: the table every lesson in this tutorial reuses

SELECT * FROM students;

id | name  | track         | score
1  | Ada   | Frontend      | 92
2  | Chidi | Cybersecurity | 78
3  | Musa  | Backend       | 85

Every example from here on queries this exact students table, worth remembering its shape (four columns: id, name, track, score), since later lessons will reference it without repeating the setup each time.

SELECT * FROM students;

id | name  | track         | score
1  | Ada   | Frontend      | 92
2  | Chidi | Cybersecurity | 78
3  | Musa  | Backend       | 85

SELECT →