We walk in the dark places no others will enter
We stand on the bridge and no one may pass

USE AdventureWorks;

SET STATISTICS IO ON
--===== All columns from an indexed table (9 reads)
 SELECT * FROM HumanResources.Employee;

--===== All columns from an identical but non-indexed table (8 reads)
 SELECT * FROM #NoIndexes;

--===== 2 columns from an indexed table (5 reads)
 SELECT EmployeeID, LoginID
   FROM HumanResources.Employee;

--===== 2 columns from an identical but non-indexed table (8 reads)
  SELECT EmployeeID, LoginID
    FROM #NoIndexes;
---------------------------------------------------------------------------
--===== All columns from an indexed table (2 reads)
 SELECT * FROM HumanResources.Employee WHERE EmployeeID = 137;

--===== All columns from an identical but non-indexed table (8 reads)
 SELECT * FROM #NoIndexes WHERE EmployeeID = 137;

--===== 2 columns from an indexed table (2 reads)
 SELECT EmployeeID, LoginID
   FROM HumanResources.Employee
  WHERE EmployeeID = 137;

--===== 2 columns from an identical but non-indexed table (8 reads)
  SELECT EmployeeID, LoginID
    FROM #NoIndexes
   WHERE EmployeeID = 137;