SELECT TOP 100 *
FROM dbo.Orders o
INNER JOIN dbo.Customers c ON c.ID = o.CustomerID
WHERE c.Email = 'nam.nguyen@ceezoo.com' AND o.IsNotified = 0

UPDATE o
SET o.IsNotified = 1
FROM dbo.Orders o
INNER JOIN dbo.Customers c ON c.ID = o.CustomerID
WHERE c.Email != 'nam.nguyen@ceezoo.com' AND o.IsNotified = 0