Need to use one and one only of multiple parameters in a stored procedure
I think something like the following pattern might work:

WHERE
  (PARAMETER1 = DBFIELD1 AND PARAMETER2 IS NULL AND PARAMETER3 IS NULL AND PARAMETER4 IS NULL)
  OR (PARAMETER2 = DBFIELD2 AND PARAMETER1 IS NULL AND PARAMETER3 IS NULL AND PARAMETER4 IS NULL)
  OR ...


That pattern is pretty ugly but it will only give you rows if one parameter is set and the others are null. In order to give you something more I'd need you to edit your question to better explain what you want.