in reply to Adding a hash to a CGI param

I believe this will work:
#EARLIER $self->param( 'sql' => \%sql ); #LATER $self->param( 'sql' )->{page_id} = 45;
Where the concept is that the value of the 'sql' param is a hash reference, so you just need to retrieve that and work with it as if it you had done something like my $href= \%sql;
In the line above, it simply deferences the return value of $self->param( 'sql' ) and sets the page_id key to 45.