VBA/SQL：如何在WHERE子句中使用Function来构建SQL？

Question

我有一种情况，我试图从描述字段拉状态值。但是，我需要根据状态更改一些列。因此，这里是我

说明示例：管理执行CTJACKSONVILLE.FL.32216-4041

Function getState(description As String) As String 
    Dim s() As String 
    s = Split(description, ".") 
    getState = s(UBound(s) - 1) 
End Function 

我想改变一些列取决于它是否返回正确的状态缩写与否。如果该值没有返回有效状态，我想标记发票。所以像这样...

UPDATE tblInvoices 
SET [Invoice Flag] = True 
Where getState(description) <> ValidStates.Abbreviation 

沿着这些线的东西。对新手而言很抱歉。任何帮助表示赞赏！

Answer 1

我想创建一个函数调用isValidState()返回一个布尔值

Function isValidState(st As String) As Boolean 
    Select Case st 
     Case "AL", "FL", "NY" ... 
      isValidState = True 
     Case Else 
      isValidState = False 
    End Select 
End Function 

另一种方式可以是让所有的状态代码表（我们称之为MyStateTable）

Function isValidState(st As String) As Boolean 
    Dim db As Database 
    Dim rs As Recordset 
    Set db = CurrentDb 
    Set rs = db.OpenRecordset("MyStateTable") 
    rs.FindFirst ("StateFieldName = '" & st & "'") 
    If rs.NoMatch Then 
     isValidState = False 
    Else 
     isValidState = True 
    End If 
    rs.Close 
End Function 

所以您的查询看起来像

UPDATE tblInvoices 
SET [Invoice Flag] = True 
Where isValidState(getState(description)) = True 

编辑：

Function getState(description As String) As String 
    Dim s() As String 
    s = Split(description, ".") 
    If (UBound(s) > 1) then 
     getState = s(UBound(s) - 1) 
    Else 
     getState = vbNullString 'Or change this to "" or something else that makes sense for your usage' 
    End if 
End Function