Hi
You have a problem in your query string please change your query:
Dim datenow As Date = Date.Now.Date
Dim sql As String = "SELECT DISTINCT cmp_user_id FROM tbl_campaign WHERE cmp_date =#" & datenow.ToString() & "#"
But I suggestion to you check the cmp_date data type from your database and be sure it is a DateTime after you should check the format of this field, for example if your cmp_date fields format at database is "dd/mm/yyyy" you should set this format on your datenow variable too ;)
Best Regards.