Question

You are an analyst in a Fabric warehouse. Two tables, [dbo].[OnlineCustomers] and [dbo].[StoreCustomers], each contain a CustomerID column. Marketing wants a single, de-duplicated list of CustomerIDs that appear in BOTH tables — customers who shopped online and in stores. Which T-SQL set operator returns exactly this result in one query?

Accepted Answer

SELECT CustomerID FROM OnlineCustomers INTERSECT SELECT CustomerID FROM StoreCustomers

Answer

SELECT CustomerID FROM OnlineCustomers UNION SELECT CustomerID FROM StoreCustomers

Answer

SELECT CustomerID FROM OnlineCustomers EXCEPT SELECT CustomerID FROM StoreCustomers

Answer

SELECT CustomerID FROM OnlineCustomers UNION ALL SELECT CustomerID FROM StoreCustomers