รบกวนช่วยเขียนคำสั่ง SQL ให้หน่อยครับ ติดมา2วันแล้วยังไม่ผ่านจริงๆครับผม

For i As Integer = 0 To ServicebilldetailDataGridView1.Rows.Count - 1
            If ServicebilldetailDataGridView1.Rows(i).Cells(5).Value IsNot Nothing Then
                Dim id As String = ServicebilldetailDataGridView1.Rows(i).Cells(1).Value.ToString()
                Dim strselectDEL As String
               strselectDEL= "declare @sdid varchar(20),@seid varchar(20),@smid varchar(20)" & vbCrLf & _
               "declare @name varchar(50),@price int" & vbCrLf & _
               "set @sdid=ServicebilldetailDataGridView1.Rows(i).Cells(0).Value.ToString()" & vbCrLf & _
              "set @seid=ServicebilldetailDataGridView1.Rows(i).Cells(1).Value.ToString()" & vbCrLf & _
              "set @smid=ServicebilldetailDataGridView1.Rows(i).Cells(2).Value.ToString()" & vbCrLf & _
              "set @name=ServicebilldetailDataGridView1.Rows(i).Cells(3).Value.ToString()" & vbCrLf & _
              "set @price=ServicebilldetailDataGridView1.Rows(i).Cells(4).Value" & vbCrLf & _
             "if(select count(*) from tablename where sdid=@sdid) = 0" & vbCrLf & _
                "begin" & vbCrLf & _
                  "insert into tablename(sdid,seid,smid,name,price) select @sdid,@seid,@smid,@name,@price" & vbCrLf & _
                "End" & vbCrLf & _
             "Else" & vbCrLf & _
                "begin" & vbCrLf & _
                 "update tablename set seid=@seid,smid=@smid,name=@name,price=@price where sdid=@sdid" & vbCrLf & _
                "End"
                com.CommandType = CommandType.Text                                  
                com.CommandText = strselectDEL                                     
                com.Connection = con                                                
                com.ExecuteNonQuery()                                              
                MsgBox("OK")

            End If
        Next