How to Change the Return Type (Select Projection)

When you write queries against a database system in SQL, specifying a set of columns to return is second nature. The goal is to limit the columns returned to only those necessary for the query in order to improve performance and limit network traffic (the less data transferred, the better). This is achieved by listing the column names after the Select clause in the following format. In most cases, only the columns of interest are returned using the SQL syntax form:

Select * from Contacts

Select ContactId, FirstName, LastName from Contacts