I know that:
$sth->fetchrow_hashref
returns a hashref of the fetched row from database,$sth->fetchrow_arrayref
returns an
You could do worse than read DBI recipes by gmax.
It notes, among other things:
The problem arises when your result set, by mean of a JOIN, has one or more columns with the same name. In this case, an arrayref will report all the columns without even noticing that a problem was there, while a hashref will lose the additional columns