我有一个MS Access数据库,其中有一个名为的字段Field1
,其中包含多个用逗号分隔的值。IE,
Value1,Value 2, Value3, Value 4,Value5
我试图将值拆分成单独的字段,而不是将其拆分为单独的字段,而是将记录复制并存储在另一个字段中。这样,包含一个具有三个值的单元格的记录将被重复三次,每个记录的新字段中所包含的值都不同。例如,
在查询/运行模块之前:
+-----------+------------------------+ | App Code | Field1 | +-----------+------------------------+ | AB23 | Value1, Value 2,Value3 | +------------------------------------+
在查询/运行模块之后:
+-----------------------------------------------+ | App Code | Field1 | Field2 | +-----------+------------------------+----------+ | AB23 | Value1, Value 2,Value3 | Value1 | +-----------+------------------------|----------+ | AB23 | Value1, Value 2,Value3 | Value 2 | +-----------+------------------------+----------+ | AB23 | Value1, Value 2,Value3 | Value3 | +-----------+------------------------+----------+
到目前为止,我发现了几个有关将一个字段拆分为 两个甚至几个不同字段的问题,但是我还没有找到任何将记录垂直拆分的解决方案。在这些解决方案中,一些使用查询,其他使用模块,但是我也不确定哪种方法最有效,因此我决定使用VBA模块。
因此,这是迄今为止我发现最有用的VBA模块:
Function CountCSWords (ByVal S) As Integer
' Counts the words in a string that are separated by commas.
Dim WC As Integer, Pos As Integer
If VarType(S) <> 8 Or Len(S) = 0 Then
CountCSWords = 0
Exit Function
End If
WC = 1
Pos = InStr(S, ",")
Do While Pos > 0
WC = WC + 1
Pos = InStr(Pos + 1, S, ",")
Loop
CountCSWords = WC
End Function
Function GetCSWord (ByVal S, Indx As Integer)
' Returns the nth word in a specific field.
Dim WC As Integer, Count As Integer, SPos As Integer, EPos As Integer
WC = CountCSWords(S)
If Indx < 1 Or Indx > WC Then
GetCSWord = Null
Exit Function
End If
Count = 1
SPos = 1
For Count = 2 To Indx
SPos = InStr(SPos, S, ",") + 1
Next Count
EPos = InStr(SPos, S, ",") - 1
If EPos <= 0 Then EPos = Len(S)
GetCSWord = Trim(Mid(S, SPos, EPos - SPos + 1))
End Function
但是,如何在访问查询中使用它来实现上述预期结果?否则,除了查询(即仅使用VBA模块)以外,还有没有更好的方法可以得出相同的结论?
编辑
请注意,表中的主键
Application Code
不是自动编号。这个主键是文本的,并且是独特的。为了拆分记录,这将需要复制主键,这很好。
这是在Table1中使用Field1,Field2的示例代码片段
Option Explicit
Public Sub ReformatTable()
Dim db As DAO.Database
Dim rs As DAO.Recordset
Dim rsADD As DAO.Recordset
Dim strSQL As String
Dim strField1 As String
Dim strField2 As String
Dim varData As Variant
Dim i As Integer
Set db = CurrentDb
' Select all eligible fields (have a comma) and unprocessed (Field2 is Null)
strSQL = "SELECT Field1, Field2 FROM Table1 WHERE ([Field1] Like ""*,*"") AND ([Field2] Is Null)"
Set rsADD = db.OpenRecordset("Table1", dbOpenDynaset, dbAppendOnly)
Set rs = db.OpenRecordset(strSQL, dbOpenDynaset)
With rs
While Not .EOF
strField1 = !Field1
varData = Split(strField1, ",") ' Get all comma delimited fields
' Update First Record
.Edit
!Field2 = Trim(varData(0)) ' remove spaces before writing new fields
.Update
' Add records with same first field
' and new fields for remaining data at end of string
For i = 1 To UBound(varData)
With rsADD
.AddNew
!Field1 = strField1
!Field2 = Trim(varData(i)) ' remove spaces before writing new fields
.Update
End With
Next
.MoveNext
Wend
.Close
rsADD.Close
End With
Set rsADD = Nothing
Set rs = Nothing
db.Close
Set db = Nothing
End Sub
编辑
更新示例以生成新的主键
如果必须基于先前的Appcode生成新的AppCode(并且将AppCode假定为文本字段),则可以使用此示例根据最后的Appcode生成唯一的主键。
Option Explicit
Public Sub ReformatTable()
Dim db As DAO.Database
Dim rs As DAO.Recordset
Dim rsADD As DAO.Recordset
Dim strSQL As String
Dim strField1 As String
Dim strField2 As String
Dim varData As Variant
Dim strAppCode As String
Dim i As Integer
Set db = CurrentDb
' Select all eligible fields (have a comma) and unprocessed (Field2 is Null)
strSQL = "SELECT AppCode, Field1, Field2 FROM Table1 WHERE ([Field1] Like ""*,*"") AND ([Field2] Is Null)"
' This recordset is only used to Append New Records
Set rsADD = db.OpenRecordset("Table1", dbOpenDynaset, dbAppendOnly)
Set rs = db.OpenRecordset(strSQL, dbOpenDynaset)
With rs
While Not .EOF
' Do we need this for newly appended records?
strAppCode = !AppCode
strField1 = !Field1
varData = Split(strField1, ",") ' Get all comma delimited fields
' Update First Field
.Edit
!Field2 = Trim(varData(0)) ' remove spaces before writing new fields
.Update
' Add new fields for remaining data at end of string
For i = 1 To UBound(varData)
With rsADD
.AddNew
' ***If you need a NEW Primary Key based on current AppCode
!AppCode = strAppCode & "-" & i
' ***If you remove the Unique/PrimaryKey and just want the same code copied
!AppCode = strAppCode
' Copy previous Field 1
!Field1 = strField1
' Insert Field 2 based on extracted data from Field 1
!Field2 = Trim(varData(i)) ' remove spaces before writing new fields
.Update
End With
Next
.MoveNext
Wend
.Close
rsADD.Close
End With
Set rsADD = Nothing
Set rs = Nothing
db.Close
Set db = Nothing
End Sub
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