Date and Time Diff Question

[Rain]

Shouldn't DateDiff return a negative value when the date is an earlier date?
The same goes for TimeDiff.

Code: Select all

GetDate>today
DateAdd>today,D,-1,yesterday
DateDiff>today,yesterday,D,NegativeDays
DateAdd>today,D,1,tomorrow
DateDiff>today,tomorrow,D,PositiveDays
mdl>Yesterday: %NegativeDays%%CRLF%Tomorrow: %PositiveDays%

[armsys]

Shouldn't DateDiff return a negative value when the date is an earlier date?
The same goes for TimeDiff.

Hi RAIN,
DateDiff means "absolute" difference between 2 dates.
If the chronological order matters, try:

Code: Select all

GetDate>today
DateAdd>today,D,-1,yesterday
DateDiff>today,yesterday,D,NegativeDays
DateAdd>today,D,1,tomorrow
DateDiff>today,tomorrow,D,PositiveDays
mdl>Yesterday: %NegativeDays%%CRLF%Tomorrow: %PositiveDays%
Let>Sign={if(%Today%>%Yesterday%,-1,1)}
MDL>Sign
Let>NegativeDays=NegativeDays*Sign
MDL>NegativeDays

Hope it meets your requirement. Thnaks for sharing your discovery.

[Rain]

Thanks for the reply, armsys.

I believe there is an issue with DateDiff because when I use DateDiff with VBScript I get a negative or positive result.

Marcus, is there an issue with DateDiff and TimeDiff?

Code: Select all

GetDate>Today
DateAdd>%Today%,d,-1,Yesterday
VBEval>DateDiff("d", "%Today%", "%Yesterday%"),NegativeDate

DateAdd>%Today%,D,1,Tomorrow
VBEval>DateDiff("d", "%Today%", "%Tomorrow%"),PositiveDate

mdl>Negative Date: %NegativeDate%%CRLF%Positive Date: %PositiveDate%

[armsys]

I believe there is an issue with DateDiff because when I use DateDiff with VBScript I get a negative or positive result.

Hi RAIN,
In actuality, there're plenty of nuanced differences between MS and VBscript. RegEx and HTTP are just 2 outstanding examples.
For DataDiff, maybe Marcus does MS users a service by yielding an absolute difference between 2 dates.
Furthermore, thanks to your thread, I expanded my test and discovered MS can't do simple date sum/difference:

Code: Select all

Let>d1=1/1/2013
Let>d2=1/2/2013
Let>d=d2-d1

It turns out that "d2-d1" is assigned to d.

[Rain]

Here is another example that includes times as well as dates.

Code: Select all

GetDate>Today
GetTime>Now

DateAdd>%Today%,D,1,Tomorrow
TimeAdd>%Now%,h,1,OneHourLater
VBEval>DateDiff("h", "%Today% %Now%", "%Tomorrow% %OneHourLater%"),DiffRes

mdl>Difference: %DiffRes% Hours

/*
Intervals:
yyyy - Year
q - Quarter
m - Month
y - Day of year
d - Day
w - Weekday
ww - Week of year
h - Hour
n - Minute
s - Second
*/

This example compares times only

Code: Select all

GetTime>Now

TimeAdd>%Now%,h,1,OneHourLater
VBEval>DateDiff("h", "%Now%", "%OneHourLater%"),DiffRes

mdl>Difference: %DiffRes% Hour

/*
Intervals:
yyyy - Year
q - Quarter
m - Month
y - Day of year
d - Day
w - Weekday
ww - Week of year
h - Hour
n - Minute
s - Second
*/

[armsys]

Here is another example that includes times as well as dates.

Hi RAIN,
Thanks for 2 more scripts on date/time differences.
In particular, I like your handy documentation at the bottom.
I'm now convinced that MS should support "signed" DateDiff command.
Reason:
1. Positive/negative difference between 2 dates is often important.
2. Save additional statements to determine the positive/negative difference.
Hope Marcus will respond your feature request.
Thanks again.

[Rain]

I'm curious if there is a bug in DateDiff and TimeDiff or if Marcus and crew meant to code it this way. Either way, I don't mind using the vbScript examples I posted.

[Grovkillen]

It would be great if I could tell MS that I want absolute or relative datediff. Maybe by a:

Let>DATEDIFF_STATE=1 (for relative)

and

Let>DATEDIFF_STATE=0 (for absolute, default)

Same for timediff...

[armsys]

Either way, I don't mind using the vbScript examples I posted.

Agree. Rain, thanks for your VBScript scripts, which benefit us all.

[armsys]

Let>DATEDIFF_STATE=1 (for relative)
and
Let>DATEDIFF_STATE=0 (for absolute, default)
Same for timediff...

Excellent idea. I love Swedish design-simple and practical. Thanks.