将单个数据库字段拆分为多个字段

Question

以下是为拆分以下表而编写的查询。第三列是后缀，此字段前面的列不会在返回字段的末尾修剪-suffix。我附上了查询以及结果和问题的图像。

SELECT Left([ADDRESS_ID],InStr([ADDRESS_ID],"-")-1) AS Abbreviation,
       Mid([ADDRESS_ID],InStr([ADDRESS_ID],"-")+1) AS CODE,
       Right([ADDRESS_ID],InStr([ADDRESS_ID],"-")) AS SUFFIX,
       MDM_Address_Remote_Key.ADDRESS_ID
FROM MDM_Address_Remote_Key;

三列分开，应该看起来像第三列;但是，中间列在末尾保持后缀。如何解决这个问题？

Answer 1

原因是mid函数需要3个参数：

Mid ( text, start_position, number_of_characters )

如果您没有指定最后一个参数，mid函数将返回start_position之后的所有字符，这将导致您的结果。

尝试：

Mid([ADDRESS_ID],InStr([ADDRESS_ID],"-")+1,InStrRev([ADDRESS_ID],"-")-(InStr([ADDRESS_ID],"-")+1)) AS CODE

Answer 2

此表达式提取我认为您想要CODE的子字符串：

Mid([ADDRESS_ID], InStr(1, [ADDRESS_ID], "-") + 1, InStrRev([ADDRESS_ID], "-") - InStr(1, [ADDRESS_ID], "-") - 1) AS CODE

然而，这个表达式相当复杂，而你的其他字段表达式已经相当复杂了 - 整个lotta函数都在继续。

如果要在Access会话中运行查询，则可以使用利用VBA Split()功能的自定义函数。

然后您的查询可以更简单明了。

SELECT SplitSegment([ADDRESS_ID], "-", 0) AS Abbreviation,
       SplitSegment([ADDRESS_ID], "-", 1) AS CODE,
       SplitSegment([ADDRESS_ID], "-", 2) AS SUFFIX,
       MDM_Address_Remote_Key.ADDRESS_ID
FROM MDM_Address_Remote_Key;

Public Function SplitSegment(ByVal pSource As Variant, _
        ByVal pDelimter As String, _
        ByVal pIndex As Long) As Variant

    Dim varOut As Variant
    varOut = Null
    If Not IsNull(pSource) Then
        varOut = Split(pSource, pDelimter)(pIndex)
    End If
    SplitSegment = varOut
End Function