SQL Server - select 1 from emp? where we use in realtime?

please suggest me where we use select 1 from emp? select 2 from emp? in realtime.

thanks in advance

Hope this helps


blog.sqlauthority.com/2008/02/26/sql-server-select-1-vs-select-an-interesting-observation/

This one looks better

http://stackoverflow.com/questions/7171041/what-does-it-mean-by-select-1-from-table