How can i find a time difference

[Appollo14]

Hello all,
I have two text fields which i convert to to a time. These times give me a delivery time and an actual delivery time. In my report i want to count all jobs where the actual delivery time is more than 30minutes greater than the delivery time.
How can i do this.
The original text goes in as 08:00 for example and is converted to time using the CTime function. If it makes any difference I'm using Crytal reports version 8.

Any suggestions?

Regards,
Noel.

 

[Appollo14]

Hi Guys,

Had a burst of inspiration just after submitting my post. I've sorted this one using the hour and minutes functions and doing a simple calculation, which is made easier by the fact that both times are on the same day.

Would still be interested to know if there is a simpler way of dealing with what appears to be a straight forward comparrison though.

Regards,
Noel.