sql - 调用函数的MS Access更新查询不返回任何内容/更新字段

我有一个文本字段Ran，并且我希望能够使用RanKeyNo5字段中出现的指定数量的字母(等值的2个数字)来更新字段Ran(更新查询)。字母按在Ran中出现的顺序排列。

例如，如果Ran包含BFHCIEALGJDK，则答案将是0203050104。

我在代码中放置了消息框来监视值，它似乎可以正常工作，但是表没有更新。

查询，“更新为”:

KeyNo([Ran],5)

Public Function KeyNo(myStr As String, intLen As Integer) As String
Dim RandomString As String, strLetter As String, PosNo As Integer, LetSelect As String, LetNo As String, Count As Integer

RandomString = "00"
PosNo = 1
Count = Len(myStr)

'MsgBox myStr

Dim i As Long
For i = 1 To Count

    LetSelect = Mid(myStr, PosNo, 1)

    If LetSelect = "A" Then
        LetNo = "01"
    ElseIf LetSelect = "B" Then
        LetNo = "02"
    ElseIf LetSelect = "C" Then
        LetNo = "03"
    ElseIf LetSelect = "D" Then
        LetNo = "04"
    ElseIf LetSelect = "E" Then
        LetNo = "05"
    ElseIf LetSelect = "F" Then
        LetNo = "06"
    ElseIf LetSelect = "G" Then
        LetNo = "07"
    ElseIf LetSelect = "H" Then
        LetNo = "08"
    ElseIf LetSelect = "I" Then
        LetNo = "09"
    ElseIf LetSelect = "J" Then
        LetNo = "10"
    ElseIf LetSelect = "K" Then
        LetNo = "11"
    ElseIf LetSelect = "L" Then
        LetNo = "12"
    ElseIf LetSelect = "M" Then
        LetNo = "13"
    ElseIf LetSelect = "N" Then
        LetNo = "14"
    ElseIf LetSelect = "O" Then
        LetNo = "15"
    ElseIf LetSelect = "P" Then
        LetNo = "16"
    ElseIf LetSelect = "Q" Then
        LetNo = "17"
    ElseIf LetSelect = "R" Then
        LetNo = "18"
    ElseIf LetSelect = "S" Then
        LetNo = "19"
    ElseIf LetSelect = "T" Then
        LetNo = "20"
    ElseIf LetSelect = "U" Then
        LetNo = "21"
    ElseIf LetSelect = "V" Then
        LetNo = "22"
    ElseIf LetSelect = "W" Then
        LetNo = "23"
    ElseIf LetSelect = "X" Then
        LetNo = "24"
    ElseIf LetSelect = "Y" Then
        LetNo = "25"
    ElseIf LetSelect = "Z" Then
        LetNo = "26"
    End If

    If Val(LetNo) <= intLen Then
        RandomString = RandomString & LetNo
'        MsgBox RandomString
    End If

    PosNo = PosNo + 1
Next

RandomString = Mid(RandomString, 3, intLen * 2)

End Function

最佳答案

它不返回任何内容，因为函数未设置为返回任何内容。最后一行应该是:
KeyNo = Mid(RandomString, 3, intLen * 2)