Write SQL query to solve given problem: How many online purchases did Ole Group make in May 2019?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT SUM(CASE WHEN T1.`Sales Channel` = 'Online' AND T2.`Customer Names` = 'Ole Group' AND T1.OrderDate LIKE '5/%/19' THEN 1 ELSE 0 END) FROM `Sales Orders` AS T1 INNER JOIN Customers AS T2 ON T2.CustomerID = T1._CustomerID