>>>>I'm assuming that '%' is included into Vp_in already, because otherwise I don't see a reason for using LIKE and not = at all.
>>>
>>>In that case, there's no need to trim, is there ?
>>
>>No need to trim, you're right. I'm wondering why Bernhart insists on trimming.
>
>
>Maybe the %'s aren't in after all

May be. I would use = when we want an exact match and LIKE only for partial matches. It is also clearer from the maintenance point of view.