Deleting Data with DELETE

DELETE removes rows from a table. Like UPDATE, always use WHERE to target specific rows.

Basic DELETE Syntax

DELETE FROM table_name WHERE condition;

Warning: Without WHERE, DELETE removes ALL rows!

Exercises

DELETE with Products

Danger: DELETE Without WHERE

-- This deletes EVERY row!
DELETE FROM users;

This is called "truncating" the table. The table structure remains, but all data is gone.

Safe Delete Pattern

Before deleting, SELECT first to see what would be deleted:

-- First, see what you're about to delete
SELECT * FROM users WHERE age < 25;

-- If that looks right, then delete
DELETE FROM users WHERE age < 25;

Free Practice

Try:

• Delete by email domain
• Delete then count to verify
• Delete and verify the specific rows are gone