Database: retail_world
Question: Of all the orders that have ordered Ikura, how many of them enjoys a unit price that's lower than its standard unit price?
SQL: SELECT COUNT(T2.OrderID) FROM Products AS T1 INNER JOIN `Order Details` AS T2 ON T1.ProductID = T2.ProductID WHERE T1.ProductName = 'Ikura' AND T2.UnitPrice < T1.UnitPrice