Microsoft KB Archive/88657

= ACC: Functions for Calculating and Displaying Date/Time Values =

Article ID: 88657

Article Last Modified on 1/18/2007

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APPLIES TO


 * Microsoft Access 1.0 Standard Edition
 * Microsoft Access 1.1 Standard Edition
 * Microsoft Access 2.0 Standard Edition
 * Microsoft Access 95 Standard Edition
 * Microsoft Access 97 Standard Edition

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This article was previously published under Q88657



Moderate: Requires basic macro, coding, and interoperability skills.



SUMMARY
Because a Date/Time value is stored as a double-precision number, you may receive incorrect formatting results when you try to manipulate Date/Time values in an expression. This article shows you how to create expressions and custom functions for displaying specific dates and calculating time intervals.

This article assumes that you are familiar with Visual Basic for Applications and with creating Microsoft Access applications using the programming tools provided with Microsoft Access. For more information about Visual Basic for Applications, please refer to your version of the &quot;Building Applications with Microsoft Access&quot; manual.

NOTE: Visual Basic for Applications is called Access Basic in Microsoft Access versions 1.x and 2.0. For more information about Access Basic, please refer to the &quot;Introduction to Programming&quot; manual in Microsoft Access version 1.x or the &quot;Building Applications&quot; manual in Microsoft Access version 2.0



Displaying Specific Dates
To display specific dates, you can use the DateSerial function to manipulate the day, month, and year portions of a date. For example, you can use the following expressions in the ControlSource property of a text box or in the Debug window (or the Immediate window in versions 1.x and 2.0) to return specific dates:

 The current month:

DateSerial(Year(Date), Month(Date), 1)

 The next month:

DateSerial(Year(Date), Month(Date) + 1, 1)

 The last day of the current month:

DateSerial(Year(Date), Month(Date) + 1, 0)

 The last day of the next month:

DateSerial(Year(Date), Month(Date) + 2, 0)

 The first day of the previous month:

DateSerial(Year(Date), Month(Date)-1,1)

 The last day of the previous month:

DateSerial(Year(Date), Month(Date),0)

</li> The first day of the current quarter:

DateSerial(Year(Date), Int((Month(Date) - 1) / 3) * 3 + 1, 1)

</li> The last day of the current quarter:

DateSerial(Year(Date), Int((Month(Date) - 1) / 3) * 3 + 4, 0)

</li> The first day of the current week (assuming Sunday = day 1):

Date - WeekDay(Date) + 1

</li> The last day of the current week:

Date - WeekDay(Date) + 7

</li> The first day of the current week (using settings in Options dialog box):

Date - WeekDay(Date, 0) + 1

</li> The last day of the current week:

Date - WeekDay(Date, 0) + 7

</li></ul>

For information about calculating the fiscal year or fiscal month, please see the following article in the Microsoft Knowledge Base:

132101 ACC: How to Get the Fiscal Year/Month of a Particular Date

Calculating Time Intervals
Because a time value is stored as a fraction of a 24-hour day, you may receive incorrect formatting results when you try to add, subtract, multiply or divide time data greater than 24 hours.

For example, if you try to find the number of hours elapsed between two dates by subtracting the values in Visual Basic, you may receive an incorrect number. To demonstrate this, type the following code in the Debug window (or Immediate window in version 2.0) and note that it returns a value of 05:00 hours rather than the correct value of 53:00 hours: StartDate=#6/1/93 8:00AM# EndDate=#6/3/93 1:00PM# ?Format(EndDate-StartDate,&quot;hh:mm&quot;) To resolve formatting problems caused by time values greater than 24 hours, you can use the Int and CSng functions in Visual Basic to separate a calculated time value into different variables for days, hours, minutes, and seconds. For example, you can include the following code fragment in a custom function to create separate time variables: '---  ' This sample code separates a time interval into seven variables for ' the following values: days, hours, minutes, seconds, total time in  ' hours, total time in minutes, and total time in seconds. '  ' The interval argument is flexible; it can be a single value, an   ' expression, or a field reference. '---

Dim totalhours As Long, totalminutes As Long, totalseconds As Long Dim days As Long, hours As Long, minutes As Long, seconds As Long Dim interval As Variant

days = Int(CSng(interval)) totalhours = Int(CSng(interval * 24)) totalminutes = Int(CSng(interval * 1440)) totalseconds = Int(CSng(interval * 86400)) hours = totalhours Mod 24 minutes = totalminutes Mod 60 seconds = totalseconds Mod 60 You can use the totalhours, totalminutes, and totalseconds variables to display a time value as a single unit of time. The days, hours, minutes, and seconds variables enable you to break down a time value into portions of time. To display time values in different formats, you can concatenate these variables as demonstrated in the following sample functions:


 * The GetElapsedDays function calculates the elapsed time between two date/time values and displays the result in days.
 * The GetElapsedTime function calculates the elapsed time between time values and displays the result in days, hours, minutes, and seconds.
 * The GetTimeCardTotal function sums a field of time values in a table and displays the total in hours and minutes.

GetElapsedDays Sample Function
To create the GetElapsedDays function, follow these steps:

<ol> Open the sample database Northwind.mdb.(or NWIND.MDB in versions 1.x and 2.0).</li> Create a module and type the following line in the Declarations section if it is not already there:

Option Explicit

</li>  Type the following function: Function GetElapsedDays (interval) Dim days As Long

days = Int(CSng(interval)) GetElapsedDays = days &&quot; Days &quot;

End Function </li> To test this function, create a new query based on the Orders table.</li> In the QBE grid, add the following fields.

In Microsoft Access version 7.0 and 97: <pre class="fixed_text">        Field: ShippedDate Show: True Field: OrderDate Show: True Field: ElapsedTime: GetElapsedDays([ShippedDate]-[OrderDate]) Show: True In Microsoft Access versions 1.x and 2.0: <pre class="fixed_text">        Field: Shipped Date Show: True Field: Order Date Show: True Field: ElapsedTime: GetElapsedDays([Shipped Date]-[Order Date]) Show: True

</li> Run the query. Note that the ElapsedTime column displays the number of days between the ShippedDate field (or Shipped Date in versions 1.x and 2.0) and OrderDate field (or Order Date in versions 1.x and 2.0) for each record in the Orders table.</li></ol>

GetElapsedTime Sample Function
To create the GetElapsedTime function, follow these steps:

<ol>  Create a new table with the following structure and save it as TimeLog. <pre class="fixed_text">     Table: TimeLog ---     Field Name: StartTime Data Type: Date/Time Format: General Date Field Name: EndTime Data Type: Date/Time Format: General Date </li>  View the TimeLog table in Datasheet view, enter the following three records, and then close the table: <pre class="fixed_text">     StartTime                 EndTime 5/10/95 4:57:00 PM       5/15/95 2:38:00 AM      5/11/95 10:17:31 AM       5/24/95 6:05:00 PM      5/18/95 9:16:43  AM       5/19/95 5:03:00 PM </li> Create a module and type the following line in the Declarations section:

Option Explicit

</li>  Enter the following function:

NOTE: In the following sample code, an underscore (_) is used as a line-continuation character. Remove the underscore from the end of the line when re-creating this code in Access Basic. Function GetElapsedTime (interval) Dim totalhours As Long, totalminutes As Long, totalseconds As _ Long Dim days As Long, hours As Long, Minutes As Long, Seconds As Long

days = Int(CSng(interval)) totalhours = Int(CSng(interval * 24)) totalminutes = Int(CSng(interval * 1440)) totalseconds = Int(CSng(interval * 86400)) hours = totalhours Mod 24 Minutes = totalminutes Mod 60 Seconds = totalseconds Mod 60

GetElapsedTime = days & &quot; Days &quot; & hours & &quot; Hours &quot; & Minutes & _ &quot; Minutes &quot; & Seconds & &quot; Seconds &quot;

End Function NOTE: The GetElapsedTime function requires that you pass it a date and a time. </li> <li>To test this function, create a new report based on the TimeLog table using the AutoReport Wizard.</li> <li>View the report in Design view.</li> <li> Add an unbound text box to the TimeLog table's detail section and set its properties as follows: <pre class="fixed_text">     Textbox: Name: ElapsedTime ControlSource: =GetElapsedTime([EndTime]-[StartTime]) Width: 3 inches </li> <li>Preview the report. Note that each record displays the total elapsed time in days, hours, minutes, and seconds.</li></ol>

GetTimeCardTotal Sample Function
To create the GetTimeCardTotal function, follow these steps:

<ol> <li> Create a new table with the following structure and save it as TimeCard. <pre class="fixed_text">     Table: TimeCard ---     Field Name: Daily Hours Data Type: Date/Time Format: Short Time </li> <li>View the TimeCard table in Datasheet view, enter the following four records, and then close the table:

8:15

7:37

8:12

8:03

</li> <li>Create a module and type the following line in the Declarations section if it's not already there:

Option Explicit

</li> <li> Type the following function: Function GetTimeCardTotal Dim db As Database, rs As Recordset Dim totalhours As Long, totalminutes As Long Dim days As Long, hours As Long, minutes As Long Dim interval As Variant, j As Integer

Set db = dbengine.workspaces(0).databases(0) Set rs = db.OpenRecordset(&quot;timecard&quot;) interval = #12:00:00 AM# While Not rs.EOF interval = interval + rs![Daily hours] rs.MoveNext Wend totalhours = Int(CSng(interval * 24)) totalminutes = Int(CSng(interval * 1440)) hours = totalhours Mod 24 minutes = totalminutes Mod 60

GetTimeCardTotal = totalhours &&quot; hours and &quot; &minutes &&quot; minutes&quot;

End Function </li> <li>To test this function, type the following line in the Debug window (or Immediate window in version 1.x and 2.0), and then press ENTER:

? GetTimeCardTotal

Note that the Debug window displays 32 hours and 7 minutes.</li></ol>

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