I am using the following code in my controller:
@monday = (Time.now).at_beginning_of_week
@friday = 5.days.since(@monday)-1.second
@sent_emails = Con
Your parameters @monday and @friday are wrong, these have to be of type "timestamp without time zone" but are created as integers, see the errormessage. SQLite doesn't have any datetime-datatypes, so dates are stored as text or integers (unix-timestamps). This is why you don't get an errormessage in SQLite.
Make sure you create timestamps like '2004-10-19 10:23:54' and you will be fine. Another option could be the PostgreSQL-function to_timestamp() to convert your unix-timestamp to a timestamp:
@sent_emails = ContactEmail.all(:conditions => ['date_sent >= to_timestamp(?) and date_sent <= to_timestamp(?)', @monday, @friday])