比较日期 - 日期格式问题

Question

在我的网络表单中，我试图计算不包括周末和节假日的休假天数。我有一个 SQL 数据库，其中假日日期采用日期格式 (yyyy-MM-dd)。用户使用格式 MM/dd/yyyy 添加日期。不算我的代码工作的周末部分。弄清楚一个日期是否是假期，如果是，不计算它是行不通的。这是我的代码。我已经尝试了所有被标记出来的东西。感谢您帮助我弄清楚如何将输入的日期与 SQL 日期进行比较。

Dim intCount As Integer
Dim temp As Integer

'Set same day as 1 <-- your preference. Though you can't work out averages if they are 0.
'Im not checking if this day is a holiday (though in theory you shouldn't have to!).
If StartDate = EndDate Then
    WorkingDays = 1 'Change me to your needs.
    Exit Function
End If

intCount = 0 ' Now we start counting days. 'If you always want to count the first day, set this to 1.

Do Until StartDate = EndDate

    'First, we find out if this day is a weekday or a weekend.
    'If weekday, 1 gets added to the number of days.
    Select Case Weekday(StartDate)
        Case Is = 1, 7
            intCount = intCount 'Weekend, so nothing added.
        Case Else
            intCount = intCount + 1
    End Select

    'Now, if this day was a holiday, we take it back off again!
    'Dim vsqldate = DateTime.ParseExact(StartDate, "yyyy-MM-dd", Nothing)
    'Dim vsqldate = StartDate.ToString("yyyy-MM-dd")
    'Dim vsqldate = fromDt.ToString("yyyy-MM-dd")
    Dim vsqldate = CDate(Format(StartDate, "yyyy-MM-dd"))

    Dim strWhere = "Holiday= #" & vsqldate & "#"  'change fieldname.

    If (DCount("Holiday", "tblCodesholidays", strWhere) > 0) Then 'Change to your field/table names.
        intCount = intCount - 1
    End If

    StartDate = StartDate.AddDays(1) 'We move to the next day.

Loop

WorkingDays = intCount

Answer 1

从 SQL Server 的角度来看，格式为“yyyymmdd”的日期被认为是语言中立的。所以，在你的 VB.Net 代码中试试这个：

Dim vsqldate As DateTime 
vsqldate = DateTime.ParseExact(StartDate.ToString("MM/dd/yyyy"))
Dim strWhere = "Holiday= '" & vsqldate.ToString("yyyyMMdd") & "'"  'change fieldname.