One idea, though quite inefficient, would be to run a loop through each of the values and checking whether the record contains one of them. But once you start specifying many many values and you have many many records it really slows down...
But I'd rather think of alternatives ways to accomplishing what you want to do.
At first I was under the impression that you want to allow users to type in whatever characters and get the relevant records, but that doesn't seem to be the case.
I don't know it is weird. the parameter field includes a few different cities that were manually entered by me. if the city in the parameter field matches the database field it will query that field.
You have a list of cities that you want them to select (as opposed to typing in say "h" and getting all the records whose city name contains the word "h").
I have a report that allows users to select multiple names and output a report showing a list of transactions performed by those users.
I used a record selection formula "{my_field} = {?my_param}" and it only displayed the records whose name corresponds to one of the names on the list.
Edited by Keikoku - 21 Dec 2010 at 9:18am