upsert_on_conflict

🔄 UPSERT with INSERT ... ON CONFLICT

Use ON CONFLICT to handle insert-or-update logic in one statement, eliminating race conditions and extra queries. Specify the constraint and the DO UPDATE action for atomic UPSERT behavior.

INSERT INTO users (email, name, last_login) VALUES
  ('alice@example.com', 'Alice', NOW())
ON CONFLICT (email) DO UPDATE
  SET name = EXCLUDED.name,
      last_login = EXCLUDED.last_login;