التحديث والحذف: التحديث والحذف

UPDATE tabella
SET    colonna1 = nuovo_valore,
       colonna2 = altra_espressione
WHERE  condizione;

-- Aumenta del 10% i prezzi di tutti i prodotti della categoria 5 (Computer):
UPDATE products
SET    price = price * 1.10
WHERE  category_id = 5;

-- Aggiorna due colonne contemporaneamente:
UPDATE orders
SET    status     = 'shipped',
       shipped_at = NOW()
WHERE  id = 12;

DELETE FROM tabella
WHERE  condizione;

-- Cancella tutte le recensioni con rating < 3:
DELETE FROM reviews
WHERE  rating < 3;

-- Cancella un ordine specifico:
DELETE FROM orders WHERE id = 999;

DELETE FROM reviews
WHERE  rating < 3
RETURNING id, customer_id, rating;

DELETE FROM customers WHERE id = 1;
-- ERROR: update or delete on table "customers" violates foreign key constraint
-- on table "orders"