从标准

Question

这会从表格Voucher_Number

的tblInvoiceLog字段中获取最大数量

我想获得最大数量，但仅限于同一表格中的字段Source等于Me.Source.Value

我不知道如何添加此条件请告知：

CODE：

Private Sub Source_AfterUpdate()    

    Dim rs As ADODB.Recordset, MyVal
    Set rs = New ADODB.Recordset
    rs.Open "SELECT MAX(Voucher_Number) from tblInvoiceLog", CurrentProject.Connection
    rs.MoveFirst
    MyVal = rs.Fields(0).Value
    Me.Voucher_Number.Value = MyVal + 1
    rs.Close
    Set rs = Nothing

End Sub

Answer 1

您应该在SQL查询中添加WHERE子句

Private Sub Source_AfterUpdate()    

    Dim rs As ADODB.Recordset, MyVal

    Dim SQL as String

    Set rs = New ADODB.Recordset

    ' If Source field is STRING type
    SQL = "SELECT MAX(Voucher_Number) from tblInvoiceLog WHERE [Source]='" & Me.Source.Value & "'"

    ' If Source field is NUMBER type
    SQL = "SELECT MAX(Voucher_Number) from tblInvoiceLog WHERE [Source]=" & Me.Source.Value 

    rs.Open SQL, CurrentProject.Connection
    rs.MoveFirst
    MyVal = rs.Fields(0).Value
    Me.Voucher_Number.Value = MyVal + 1
    rs.Close
    Set rs = Nothing

End Sub

Answer 2

Private Sub Source_AfterUpdate（）

Dim rs As ADODB.Recordset, MyVal
Set rs = New ADODB.Recordset
rs.Open "SELECT MAX(Voucher_Number) from tblInvoiceLog where source="&me.source.value, CurrentProject.Connection
rs.MoveFirst
MyVal = rs.Fields(0).Value
Me.Voucher_Number.Value = MyVal + 1
rs.Close
Set rs = Nothing

End Sub