MS Access query, how to use SQL to group single dates into weeks

问题

I currently have two tables. One has Employee Names and a number associated to that name.

The other date has time sheet date with columns for the employee number, the date and the number of hours worked on that date.

I want to create a cross tab query that shows the employee names in one column with the date for the end of the week in each column, then show to sum of hours for that week for a particular employee.

My current query works but only groups by month. I am struggle to work out how to group days into weeks.

TRANSFORM Sum(tblTimeSheetData.WorkHours) AS SumOfHours
SELECT tblEmployees.Combined
FROM tblTimeSheetData RIGHT JOIN tblEmployees ON tblTimeSheetData.EmployeeID = 
tblEmployees.EmployeeID
GROUP BY tblEmployees.Combined
ORDER BY tblEmployees.Combined, Format([WorkDate],"yyyy-mm")
PIVOT Format([WorkDate],"yyyy-mm");

回答1:

As the first and last week numbers cross calendar years, both year and week number must be included:

Option Compare Database
Option Explicit

    Public Const MaxWeekValue           As Integer = 53
    Public Const MinWeekValue           As Integer = 1
    Public Const MaxMonthValue          As Integer = 12
    Public Const MinMonthValue          As Integer = 1

' Returns, for a date value, a formatted string expression with
' year and weeknumber according to ISO-8601.
' Optionally, a W is used as separator between the year and week parts.
'
' Typical usage:
'
'   FormatWeekIso8601(Date)
'   ->  2017-23
'
'   FormatWeekIso8601(Date, True)
'   ->  2017W23
'
' 2017-04-28. Gustav Brock, Cactus Data ApS, CPH.
'
Public Function FormatWeekIso8601( _
    ByVal Expression As Variant, _
    Optional ByVal WeekSeparator As Boolean) _
    As String

    Const Iso8601Separator  As String = "W"
    Const NeutralSeparator  As String = "-"

    Dim Result              As String

    Dim IsoYear As Integer
    Dim IsoWeek As Integer

    If IsDate(Expression) Then
        IsoWeek = Week(DateValue(Expression), IsoYear)
        Result = _
            VBA.Format(IsoYear, String(3, "0")) & _
            IIf(WeekSeparator, Iso8601Separator, NeutralSeparator) & _
            VBA.Format(IsoWeek, String(2, "0"))
    End If

    FormatWeekIso8601 = Result

End Function

' Returns the ISO 8601 week of a date.
' The related ISO year is returned by ref.
'
' 2016-01-06. Gustav Brock, Cactus Data ApS, CPH.
'
Public Function Week( _
    ByVal Date1 As Date, _
    Optional ByRef IsoYear As Integer) _
    As Integer

    Dim Month       As Integer
    Dim Interval    As String
    Dim Result      As Integer

    Interval = "ww"

    Month = VBA.Month(Date1)
    ' Initially, set the ISO year to the calendar year.
    IsoYear = VBA.Year(Date1)

    Result = DatePart(Interval, Date1, vbMonday, vbFirstFourDays)
    If Result = MaxWeekValue Then
        If DatePart(Interval, DateAdd(Interval, 1, Date1), vbMonday, vbFirstFourDays) = MinWeekValue Then
            ' OK. The next week is the first week of the following year.
        Else
            ' This is really the first week of the next ISO year.
            ' Correct for DatePart bug.
            Result = MinWeekValue
        End If
    End If

    ' Adjust year where week number belongs to next or previous year.
    If Month = MinMonthValue Then
        If Result >= MaxWeekValue - 1 Then
            ' This is an early date of January belonging to the last week of the previous ISO year.
            IsoYear = IsoYear - 1
        End If
    ElseIf Month = MaxMonthValue Then
        If Result = MinWeekValue Then
            ' This is a late date of December belonging to the first week of the next ISO year.
            IsoYear = IsoYear + 1
        End If
    End If

    ' IsoYear is returned by reference.
    Week = Result

End Function

If you just want to pivot on the ultimo week date, you can use this expression:

DateAdd("d", 7 - Weekday([WorkDate], vbMonday), [WorkDate])

This assumes ISO week numbering where Monday is the first day of the week.

回答2:

You can try getting the week with datepart function like

SELECT DATEPART(ww, 'your date') AS week;

and then group by week.

Here more info https://www.w3schools.com/sql/func_sqlserver_datepart.asp

来源：https://stackoverflow.com/questions/57211964/ms-access-query-how-to-use-sql-to-group-single-dates-into-weeks