#!/usr/bin/perl -Tw

use strict;
use CGI qw(:standard);
use DBI;

# connect to the database
my $dbh = DBI->connect(
   qw(DBI:mysql:database:host user pass),
) or die $DBI::errstr;

# prepare the SQL statement
my $sth = $dbh->prepare('
   select foo from baz
   where bar = ?
') or die "prepare failed";

# feed the SQL statement the criteria
$sth->execute(8) or die "execute failed";

# get an array of the fetched row - since
# we are only grabbing one field ...
my @row = $sth->fetchrow_array(); 

# we will store it in a scalar
my $field = $row[0];

# print the HTML
print header,
   start_html,start_form,
   textfield(-name=>'foo',-value=>$field),
   end_form,end_html,

# clean up
$sth->finish;
$dbh->disconnect;
[download]

(update - added shebang line to include taint option)

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)