Um, no it is not the syntax of bind_columns. To quote the DBI docs:

The list of references should have the same number of elements as the number of columns in the SELECT statement.

You have three elements in the bind_columns and only two columns in your SELECT statement. You still haven't told us what the warning, error message, or unexpected behaviour is, so it's hard to guess what is going on.

update Oops, reading further in the DBI docs, I see it does allow an ignorable undef as the first param, sorry:

For compatibility with old scripts, the first parameter will be ignored if it is undef or a hash reference.