Newsgroup: it.comp.software.database
Titolo: Come si sommano le ore in access??

Ciao, ho un campo ore entrata e uno ora uscita in formato date/ora e
devo calcolare il totale delle ore facendo la sottrazione ora uscita -
ora entrata, non ci riesco mi spiegate se si può fare in access97 e
come?? THX!!

"KiKKo" <kikkos...@interfreeTOGLI2.it> ha scritto

se li hai messi come campo data, direi che puoi usare datediff. sotto ti
metto il relativo msdn per vb. controlla se va anche con vba di access. se
funziona come in vb scrivi datediff nel codice e premi f1.
seno' mi sa a mano.
j.
DateDiff Function
Returns a Variant (Long) specifying the number of time intervals between two
specified dates.
Syntax
DateDiff(interval, date1, date2[, firstdayofweek[, firstweekofyear]])
The DateDiff function syntax has thesenamed arguments:
Part Description
interval Required.String expression that is the interval of time you use to
calculate the difference between date1 and date2.
date1, date2 Required; Variant (Date). Two dates you want to use in the
calculation.
firstdayofweek Optional. Aconstant that specifies the first day of the week.
If not specified, Sunday is assumed.
firstweekofyear Optional. A constant that specifies the first week of the
year. If not specified, the first week is assumed to be the week in which
January 1 occurs.
Settings
The intervalargument has these settings:
Setting Description
yyyy Year
q Quarter
m Month
y Day of year
d Day
w Weekday
ww Week
h Hour
n Minute
s Second
The firstdayofweek argument has these settings:
Constant Value Description
vbUseSystem 0 Use the NLS API setting.
vbSunday 1 Sunday (default)
vbMonday 2 Monday
vbTuesday 3 Tuesday
vbWednesday 4 Wednesday
vbThursday 5 Thursday
vbFriday 6 Friday
vbSaturday 7 Saturday
Constant Value Description
vbUseSystem 0 Use the NLS API setting.
vbFirstJan1 1 Start with week in which January 1 occurs (default).
vbFirstFourDays 2 Start with the first week that has at least four days in
the new year.
vbFirstFullWeek 3 Start with first full week of the year.
Remarks
You can use the DateDiff function to determine how many specified time
intervals exist between two dates. For example, you might use DateDiff to
calculate the number of days between two dates, or the number of weeks
between today and the end of the year.
To calculate the number of days between date1 and date2, you can use either
Day of year ("y") or Day ("d"). When interval is Weekday ("w"), DateDiff
returns the number of weeks between the two dates. If date1 falls on a
Monday, DateDiff counts the number of Mondays until date2. It counts date2
but not date1. If interval is Week ("ww"), however, the DateDiff function
returns the number of calendar weeks between the two dates. It counts the
number of Sundays between date1 and date2. DateDiff counts date2 if it falls
on a Sunday; but it doesn't count date1, even if it does fall on a Sunday.
If date1 refers to a later point in time than date2, the DateDiff function
returns a negative number.
The firstdayofweek argument affects calculations that use the "w" and "ww"
interval symbols.
If date1 or date2 is adate literal, the specified year becomes a permanent
part of that date. However, if date1 or date2 is enclosed in double
quotation marks (" "), and you omit the year, the current year is inserted
in your code each time the date1 or date2 expression is evaluated. This
makes it possible to write code that can be used in different years.
When comparing December 31 to January 1 of the immediately succeeding year,
DateDiff for Year ("yyyy") returns 1 even though only a day has elapsed.
DateDiff Function Example
This example uses the DateDiff function to display the number of days
between a given date and today.
Dim TheDate As Date   ' Declare variables.
Dim Msg
TheDate = InputBox("Enter a date")
Msg = "Days from today: " & DateDiff("d", Now, TheDate)
MsgBox Msg