Limit Report Results Based on User Logon

Sometimes there's a need to add security to your SSRS report.  You can limit what values your users can see by adding a new parameter and modifying your "where" clause to equal the user - that way they can only see what they have rights to:

Create a parameter called User 
     with a Default Value:  

=Right(User!UserID, Len(User!UserID)-InStr(User!UserID,"\"))

And in your DataSet add Parameter:
     Name: @User
     Value: =Parameters!User.Value

Add a WHERE Clause to your Dataset:
     WHERE n.LoginID=@User

Should be good to go!