Should primary keys be always assigned as clustered index

Question

I have a SQLServer table that stores employee details, the column ID is of GUID type while the column EmployeeNumber of INT type. Most of the time I will be dealing with Emp

Answer 1

Clustered indexes cause the data to be physically stored in that order. For this reason when testing for ranges of consecutive rows, clustered indexes help a lot.

GUID's are really bad clustered indexes since their order is not in a sensible pattern to order on. Int Identity columns aren't much better unless order of entry helps (e.g. most recent hires)

Since you're probably not looking for ranges of employees it probably doesn't matter much which is the Clustered index, unless you can segment blocks of employees that you often aren't interested in (e.g. Termination Dates)