SQL, how to delete data and tables

Use DELETE to remove rows while keeping the table:

DELETE FROM people
WHERE id = 2;

Start with a SELECT using the same condition:

SELECT id, name
FROM people
WHERE id = 2;

This preview does not make the later delete safe by itself. Data can change between statements. For important work, use a transaction and inspect the affected-row count before committing.

This valid statement removes every row:

DELETE FROM people;

The table and its schema remain. DROP TABLE removes the table definition and its data:

DROP TABLE people;

Treat those as different operations. A migration may drop a retired table after a compatibility period. An application normally deletes particular rows.

Foreign keys can reject a delete when other rows still reference the target. A cascading foreign key can remove those child rows automatically. Read the relationship before assuming either behavior.

NULL follows the same three-valued logic as other filters. WHERE deleted_at < CURRENT_TIMESTAMP ignores rows where deleted_at is NULL, which is often exactly what a cleanup wants.

A backup is the recovery plan for a committed accidental delete. A transaction rollback works only before commit.

Your action is to write a SELECT and matching DELETE for one disposable row. Run both inside a transaction, inspect the result, and roll it back.