Special thanks to blokhead for suggesting DBI->trace, which I was unaware of. It turns out that the problem wasn't in the query at all, but in a subsequent query. The reason it would fail on "parent" and work on "id" or "name" is that the latter would result in a different program branch - one that didn't lead to the real error location.

I'd set $dbh->{ShowErrorStatement} = 1, but the error logs were showing the wrong query. I hesitate to suggest an error in the DBI package is more likely than my simply not understanding how it works - maybe someone could shed a bit more light on the issue?

Once again, thanks for the help.
James Beninger