Please list the names of customers who have total orders of over 3 in 2018.
total orders of over 3 in 2018 refer to COUNT(OrderNumber) > 3 where SUBSTR(OrderDate, -2) = '18';
SELECT DISTINCT IIF(COUNT(T2.CustomerID) > 3, T2.`Customer Names`, NULL) FROM `Sales Orders` AS T1 INNER JOIN Customers AS T2 ON T2.CustomerID = T1._CustomerID WHERE T1.OrderDate LIKE '%/%/18' GROUP BY T1._CustomerID HAVING COUNT(T2.CustomerID)