program will crash when calling RowNumber() function of Result which is returned by DDL or insert/update/delete statement

[romberli]

program will panic when calling RowNumber() function of Result which is returned by DDL or insert/update/delete statement

how to repeat:

sql := `create table if not exists t01(id int);`
result, err := conn.Execute(sql)
if err != nil {
    fmt.Println(err.Error())
}
fmt.Println(result.RowNumber())

result.RowNumber() will cause panic, I know getting row number of those statements is meaningless,
but I think it's better to return zero rather than panic the whole program.

how to fix:
I've created a PR #578