SQL Intro

SQL — Structured Query Language — is the language for reading, writing, and shaping data in a relational database. Almost every back-end you'll ever build sits on top of it.

What SQL does

Where SQL runs

• MySQL / MariaDB — the LAMP-stack default, behind countless web apps.
• PostgreSQL — feature-rich open source DB; favoured for new projects.
• SQLite — single-file DB embedded in phones, browsers, and Laravel test suites.
• SQL Server — Microsoft's flagship database.
• Oracle / Db2 — enterprise heavyweights.

One shape, many flavours

The core grammar — SELECT cols FROM table WHERE cond — is the same everywhere. Differences appear around date functions, paging (LIMIT vs TOP), and JSON support. This tutorial flags those forks where they matter.

Example

-- A query reads rows from a table
SELECT * FROM customers;

Exercise

Test yourself