How many online sales were made in May 2018 where products were shipped from Norman?
online sales refer to OrderNumber where Sales Channel = 'Online'; May 2018 refers to OrderDate LIKE '5/%/18'; Norman is the name of the city;
SELECT SUM(CASE WHEN T1.OrderDate LIKE '5/%/18' AND T1.`Sales Channel` = 'Online' AND T2.`City Name` = 'Norman' THEN 1 ELSE 0 END) FROM `Sales Orders` AS T1 INNER JOIN `Store Locations` AS T2 ON T2.StoreID = T1._StoreID