>I was thinking that it may be something like that, do you know if i can use something like get_date_info_only(datetime_field)?
The best approach IMO, is to stick to the universal format YYYYMMDD HH:MM for datetimes in SQL Server. If you're sending DateTime parameters you don't have to worry about it, but if you're building strings, use it.
Also, while you don't need to add anything for FROM dates in queries, you can add 23:59 to TO dates, or just internally add a day and compare with < (not <=).
Hope this helps,