Since you have your answer already, I'll instead give a couple of small suggestions that you might use to simplify your code. Have a look at the selectcol_arrayref method in DBI. It will simplify your code quite a bit
my $opts = $dbh->selectcol_arrayref(<<"");
SELECT DISTINCT market
FROM table
ORDER BY market ASC
print qq{<select name="market" size="1">};
print map { qq{<option value="$_">$_</option>\n} } @$opts;
print qq{</select>};
Also, this is one of the few cases where the HTML generation utilities in CGI.pm can come in handy:
print $q->popup_menu(-name => 'market',
-size => 1,
-values => $opts);