[jackielii]

I have an alternative solution to work with an existing struct that you can't change, e.g. protobuf generated code: https://jackieli.dev/posts/pointers-in-go-used-in-sql-scanne...

  type nullString struct {
    s *string
  }
  
  func (ts nullString) Scan(value interface{}) error {
    if value == nil {
        *ts.s = "" // nil to empty
        return nil
    }
    switch t := value.(type) {
    case string:
        *ts.s = t
    default:
        return fmt.Errorf("expect string in sql scan, got: %T", value)
    }
    return nil
  }
  
  func (n *nullString) Value() (driver.Value, error) {
    if n.s == nil {
        return "", nil
    }
    return *n.s, nil
  }

Then use it:

  var node struct { Name string }
  db.QueryRow("select name from node where id=?", id).Scan(nullString(&node.Name))