SELECT t1.customerInformation.customerid AS CustomerId FROM EndUserNotificationHistoryEvent t1 WHERE t1.operationType <> 'DELETE';
In this above query where condition should be executed only when operationType column is present in the table. If operationType column is not present where condition is no needed.
Advertisement
Answer
Try This:
SELECT t1.customerInformation.customerid AS CustomerId FROM EndUserNotificationHistoryEvent t1 WHERE (t1.operationType <> 'DELETE' OR t1.operationType IS NULL)