my $sql = "SELECT DISTINCT id FROM mytable WHERE active = ?";
my $ref =  $dbh->selectall_arrayref($sql,undef,'yes');
@id = map{ $_->[0] } @$ref;
die join (", ", @id), "\n";

##</code><code>##

my $sql = "SELECT DISTINCT id FROM mytable WHERE open = ?";
my $ref =  $dbh->selectall_arrayref($sql,undef,'true');
@id = map{ $_->[0] } @$ref;
die join (", ", @id), "\n";
##</code><code>##

'open'
'\open\'

"open"
"\open\"

'\"open\"'
\"'open'\"

'"open"'
"'open'"

\'\"open\"\'
\"\'open\'\"