How can I set up a search list for a date in a time period?

Question:

Every user shall determine a time period in which he would to offer something. So he sets a start date and an end date for the time period.
How can I have an search in a list with only one choosable date for finding user profiles, in which the date is after the start date and before the end date of the time period?

Thanks, best regards

You can't. Date fields don't communicate with one another so it has no clue an end date field even exists. You'd need to have both the start and end date fields searchable and users will need to fill both out. The alternative is to code a fieldtype plugin that specifically adds that custom search behavior.