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Asked: 2026-05-11T02:49:37+00:00

I’m trying to basically do a search through the database with Perl to tell

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I’m trying to basically do a search through the database with Perl to tell if there is an item with a certain ID. This search can return no rows, but it can also return one.

I have the following code:

my $th = $dbh->prepare(qq{SELECT bi_exim_id FROM bounce_info WHERE bi_exim_id = '$exid'}); $th->execute(); if ($th->fetch()->[0] != $exid) {         ...

Basically, this tries to see if the ID was returned and if it’s not, continue with the script. But it is throwing a Null array reference error on the $th->fetch()->[0] thing. How can i just simply check to see if it returned rows or now?

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1 Answer

  1. my $th = $dbh->prepare(qq{SELECT bi_exim_id FROM bounce_info WHERE bi_exim_id = '$exid'}); $th->execute(); my $found = 0; while ($th->fetch())  {    $found = 1; }

    Your query won’t return anything if the row doesn’t exist, so you can’t de-reference the fetch.

    Update: you might want to re-write that as

    my $found = $th->fetch();
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