SQL DELETE Statement

DELETE removes rows from a table, one row at a time, optionally filtered by a WHERE clause.

Syntax

DELETE FROM table_name
WHERE condition;

Example

DELETE FROM employees
WHERE department = 'Marketing' AND status = 'resigned';

Deleting Every Row (Still Keeps the Table)

DELETE FROM employees;

This removes all rows but — unlike TRUNCATE — it's logged row-by-row, fires any DELETE triggers, and is fully transactional (can be rolled back before commit).

DELETE vs TRUNCATE vs DROP — Quick Recap

Practical Use Case

Removing specific outdated or invalid records — cancelled orders, expired sessions, duplicate signups — where you need precise control over which rows go.

Common Mistakes

• Forgetting WHERE — same risk as UPDATE: DELETE FROM employees; with no condition wipes the whole table
• Deleting a parent row that's still referenced by a foreign key elsewhere — the database will usually block this unless cascading delete is configured
• Reaching for DELETE when you actually want to clear an entire table fast — TRUNCATE is the better tool there

Interview Relevance

Almost always paired with the TRUNCATE/DROP comparison question. Also expect: "how do you delete duplicate rows, keeping only one copy?" — a classic subquery/window-function problem covered in ROW_NUMBER.

Practice Question

Write a statement that deletes all orders with a status of 'cancelled' that were placed more than a year ago.

Related SQL Notes

• TRUNCATE TABLE
• DROP TABLE
• UPDATE