SQL Comments

Comments are notes or explanations you add inside your SQL code to make it easier to understand — both for yourself and others reading your queries later. They don’t affect how the SQL runs.

✍️ Why Use Comments?

• Explain complex queries
• Temporarily disable code during debugging
• Document assumptions or reminders
• Improve code maintainability when working in teams

🛠️ How to Write Comments in SQL

There are two main ways to add comments:

1. Single-line Comments

Start with two hyphens (--)
Everything after -- on that line is a comment.

SELECT * FROM employees;  -- Get all employee records

2. Multi-line (Block) Comments

Enclosed between /* and */
Can span multiple lines.

/*
  This query fetches all employees
  whose salary is above 50000
*/
SELECT * FROM employees WHERE salary > 50000;

💡 Tips for Using Comments

• Use comments to clarify why you wrote something, not what the code does (the code itself should be clear).
• Avoid excessive commenting — keep comments relevant and concise.
• Remove or update comments when the code changes.

🧠 Quick Recap