帮我修一下代码

Private Sub Command3_Click()
On Error GoTo Err_Command3_Click

 Dim rst    As DAO.Recordset
    Dim rst1   As DAO.Recordset
    Dim i      As Double
    Set rst = CurrentDb.OpenRecordset("SELECT 进货还款.供应商, Sum(进货还款.还款金额) AS 金额合计,Sum(进货还款.折扣金额) AS 折扣合计 FROM 进货还款 GROUP BY 进货还款.供应商;")

    rst.MoveLast
    rst.MoveFirst
    Do Until rst.EOF
        i = rst!金额合计
        j = rst!折扣合计
        Set rst1 = CurrentDb.OpenRecordset("SELECT 进货表.* FROM 进货表 where 供应商='" & rst!供应商 & "'")
        With rst1
            .MoveLast
            .MoveFirst
            Do Until .EOF
                .Edit
                If i + j >= !进货金额 Then
                    !进货还款 = !进货金额 - !折扣金额
                    !进货欠款 = 0
                    i = i + j - !进货金额
                Else
                    !进货还款 = i
                    !折扣金额 = j
                    !进货欠款 = !进货金额 - !进货还款 - !折扣金额
                    i = 0
                    j = 0
                End If
                .Update
                .MoveNext
            Loop
        End With
        rst.MoveNext
    Loop
    rst1.Close
    Set rst1 = Nothing
    rst.Close
    Set rst = Nothing
   MsgBox "ok!"

Exit_Command3_Click:
    Exit Sub

Err_Command3_Click:
    MsgBox Err.Description
    Resume Exit_Command3_Click
   
End Sub