select top 3 *
from tableName
order by col3 desc

i'm not quite sure what you are trying to do here, but there are 2 things

first you are referencing R3 outside of its scope, second you have a where instead of an and, here is my shot at what i...

Ok, just wanted to make sure we aren't chasing a ghost

Rather than just adding the parameters with a name and value, try to add them with a name and type

SqlParameter param1 = new...

select db_name()

The issue is because you are placing the constraints on the same table

Think of it this way, if you remove a trip in the middle of the sequence, it will cause all other trips that are fk'd from it...