In case of a simple select from a single column the proper way to do is like this:
SELECT column_name,column_name FROM table_name;
or
SELECT * FROM table_name;
you need to specify column name in case SQL Joins or when you select from 2 or more tables having same columns name. For ex
SELECT Orders.ID AS custom_alias1, Customers.ID AS custom_alias2, Orders.OrderDate FROM Orders INNER JOIN Customers ON Orders.CustomerID=Customers.CustomerID;
As you can see ID is a column with same name in both tables and you need to specify the table name for each ID when creating the Query. Also it's good to give a name (aliases) to column fields having the same name in order not to mix the values.