I am slowly making my way through the SQL tutorial and have got a bit stuck on the exists tutorials. This is one of the examples, but I do not understand why they have used SELECT ProductName.
SELECT supplierid, SupplierName
WHERE EXISTS (SELECT ProductName FROM Products WHERE SupplierId = Suppliers.supplierId AND Price < 20);
When running SQL it provides 2 columns, supplier ID and Supplier Name as per the 1st line. I have replaced ProductName with * and get the same results, is it a best practice thing, or have I been getting worked up over not much as they just needed something to fill the space?