In general you can't see the SQL after the placeholders have been bound - at least not for those drivers and databases that use server-side prepare. The reason is that DBI never sees the SQL with the values inserted. Instead it uses the server API to send the SQL with the placeholders to the server, and then just sends the values for each
execute() iteration.
The DBI->trace() functionality may list the bound parameters - for example using DBI->trace(3) with DBD::Sybase will show this data (along with a lot of other stuff!)
Michael