How many non-discontinued products are there in the dairy category?
non-discontinued products in the dairy category refer to ProductID where Discontinued = 0 and CategoryName = 'Dairy Products';
SELECT COUNT(T1.CategoryID) FROM Categories AS T1 INNER JOIN Products AS T2 ON T1.CategoryID = T2.CategoryID WHERE T1.CategoryName = 'Dairy Products' AND T2.Discontinued = 0