Date/Time Combination and DateTimeDiff to be Returned as Time

[RSchomer]

Working with date and time in Altyerx has proven to be much more difficult than I had originally anticipated.  I have a data set which is returned to me with date and time in two separate fields.  I have two problems I'm trying to tackle and need some assistance.

First, I need to combine the date and time fields into one (the time field is also an integer, not time... solved here), and second I need to subtract time (in whole minutes) from the resulting field to return a time value.  I also need to account for possible null date and time values.  

This is pretty much what the incoming data set will look like (if there's a date, there will always be a time; but not always a brief):

Date	Time	Brief
2017-09-01 00:00:00	700	60
2017-09-01 00:00:00	1650	90
[Null]	[Null]	[Null]
2017-09-01 00:00:00	915	30
2017-09-01 00:00:00	15	30
2017-09-01 00:00:00	1130	[Null]

And this is what I want returned in the Report field (Date + Time - Brief):

Date	Time	Brief	Report
2017-09-01 00:00:00	700	60	2017-09-01 06:00:00
2017-09-01 00:00:00	1650	90	2017-09-01 15:20:00
[Null]	[Null]	[Null]	[Null]
2017-09-01 00:00:00	915	30	2017-09-01 08:45:00
2017-09-01 00:00:00	15	30	2017-08-31 23:45:00
2017-09-01 00:00:00	1130	[Null]	2017-09-01 11:30:00

Any help for an Alteryx newbie?

[pcatterson · Accepted solution]

Familiarize yourself with the DateTime functions, they are great.  Here is my approach.

[RSchomer]

I must've tried a hundred different variations of formulas before you sent that workflow.  Having the Report field type set to a string looks like it made all the difference.  I kept trying to convert it to a datetime or a double with varying unsatisfactory results.  But this workflow helped explain a lot of the little things I was missing.