In this case I will go with datetime data type. It would be easier to pull records with conditions you specified.

>
>One field of datetime or two fields, one for date and one for time?
>
>My client goal is to type&retrieve when to call back to customer (for example another 2 minutes, 30 minutes, another three days 18:00 PM etc)
>I have to retrieve data with queries by date, by time (next half hour) etc
>In addition by combination of date\time range and priority and to order by few options.
>
>I know something abut converting from datetime to date and time and opposite, but what is better?
>
>Tnk