MS Access: Query: How can I round a datetime field to the nearest hour?

I have a datetime field with both a date and a timestamp. I need to round the field to the nearest hour in a MS Access query.
Ryan SimmonsBusiness Analyst IIIAsked:
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Gustav BrockCIOCommented:
This function will do:
Public Function DateRound( _
  ByVal datDate As Date, _
  Optional ByVal intHours As Integer, _
  Optional ByVal intMinutes As Integer, _
  Optional ByVal intSeconds As Integer) _
  As Date
  
' Rounds datDate to hours and/or minutes and/or seconds as
' specified in parameters intHours, intMinutes, and intSeconds.
'
' Will accept any value within the range of data type Date:
'
'   From 100-01-01 00:00:00 to 9999-12-31 23:59:59
'
' In case the range is exceeded due to rounding, the min. or max.
' value will be returned.
'
' Examples:
'   DateRound(#9999-12-31 23:57:50#,0,5,0)
'     returns: 9999-12-31 23:59:59
'   DateRound(#9999-12-31 23:57:10#,0,5,0)
'     returns: 9999-12-31 23:55:00
'   DateRound(#9999-12-30 22:57:50#,0,5,0)
'     returns: 9999-12-30 23:00:00
'   DateRound(#2015-02-28 12:37:50#,0,15,0)
'     returns: 2015-02-28 12:45:00
'   DateRound(#2015-05-05 11:27:52#,3,0,0)
'     returns: 2015-05-05 12:00:00
'   DateRound(#2015-05-25 11:11:13#,0,0,2)
'     returns: 2015-05-25 11:11:14
'
'   Round to the tenth of a day:
'   DateRound(#2012-11-15 15:00:00#, 2, 24, 0)
'     returns: 2012-11-15 14:24:00
'
' 2008-04-16. Gustav Brock, Cactus Data ApS, CPH.
' 2010-05-12. Modified CDate expression.

  Dim datRounding As Date
  
  On Error GoTo Err_DateRound
  
  datRounding = TimeSerial(intHours, intMinutes, intSeconds)
  If datRounding <= 0 Then
    ' Round to the second.
    datRounding = TimeSerial(0, 0, 1)
  End If
  ' Apply CDec to prevent rounding errors from Doubles and allow large values.
  datDate = CDate(Int(CDec(datDate) / CDec(datRounding) + 0.5) * datRounding)
  
Exit_DateRound:
  DateRound = datDate
  Exit Function
  
Err_DateRound:
  If datDate < 0 Then
    datDate = #1/1/100#
  Else
    datDate = #12/31/9999 11:59:59 PM#
  End If
  Resume Exit_DateRound
  
End Function

Open in new window

So:

    DateRounded: DateRound([YourDateField],1,0,0)

/gustav

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DatabaseMX (Joe Anderson - Microsoft Access MVP)Database Architect / Systems AnalystCommented:
:-)
Ryan SimmonsBusiness Analyst IIIAuthor Commented:
Thank you so much!
Gustav BrockCIOCommented:
You are welcome!

/gustav
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