What does that first '?' mark mean? It makes no sense unless you are setting the value of id to '?'.

? as placeholder is only meaningful when you prepare the statement, not at the time you execute it. I think you missed the true meaning of placeholder.

For auto-increment field, you don't set value for it, otherwise what does that'auto-' mean? just take that field out from the insert statement, and database will fill in the right value for you.