In the course of debugging something, there's this bit of code which is causing a lot of fuss: 
my $sth = $dbh->prepare("
                      INSERT INTO web_sessions_aux 
                      (wsa_id, wsa_type, wsa_key, wsa_value)
                      VALUES (?,?,?,?)");

foreach my $key (keys %$pairs) {
     my $key_value = defined($pairs->{$key})?
                             $pairs->{$key} : '';

     $sth->execute($id,$type,$key,$key_value);
}

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For some as-of-yet undetermined reason, MySQL was producing errors like this:
DBD::mysql::st execute failed: Unknown column 'RTEST' in 'field list' at /usr/local...
Now 'RTEST' was one of the possible $key_value values. Why was this being interpreted as a field? Placeholder bug? Bad SQL? Not sure. One thing that made it "go away" was:
$sth->execute($id,$type,$key,"$key_value");
How can a scalar be broken in such a way? This is under Perl 5.8.0.

In reply to DBD::mysql Unusual Behavior by tadman

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