Subtracting MINUES from a Date/Time

[smilbert]

I have an APPOINTMENT Date/Time field in SQL. I also have a LeadTime (number of minutes) that need to be subracted to show an ARRIVAL time (no need for the date).

I first tried to subtract the NUMBER from the Time(APPT), but it subtracted seconds. Next, I tried using
Time(0,LeadTime,0), but it didn't like Minutes being greater than 60 (it is either 15 or 90 minutes).

I added an if/then to change 90 into Time(1,30,0), but now my answer is a number like 33,300.

Is there an easier way to do this?
What do I have to do to convert the 33,000 into a TIME?

 

[synapsevampire]

Try:

Dateadd("n",{table.minutes}*-1,{table.datetime})

or

dateserial(year({table.datetime}),hour({table.datetime}),{table.minutes}*-1)

-k