ok, here is the code I put together from the really helpful response. it runs with no errors, it just doesn't download... I must be missing something.

$host = "localhost";
$port = "3306";
$dbdriver='mysql';
$tablename = "linktable";
print "Enter year and month to download in format YYYYMM:";
$date = <STDIN>;
chomp $date;
$dsn = "dbi:$dbdriver:$database:$host:$port";
$path='/data/';
my $dbh = DBI->connect($dsn, $user, $password)
  or die "Couldn't connect to database: " . DBI->errstr;
$dbh-> do("DROP TABLE IF EXISTS LINKTABLE");
$dbh-> do("CREATE TABLE IF NOT EXISTS LINKTABLE(document_id CHAR(9),IN
+DEX(DOCUMENT_ID),PUBLISH_DATE CHAR(8),URL CHAR(150))");
$dbh-> do("LOAD DATA LOCAL INFILE '/data/DATA.CSV' INTO TABLE $tablena
+me(DOCUMENT_ID,PUBLISH_DATE)");
$dbh-> do("UPDATE LINKTABLE SET URL=CONCAT('www.example.com/document/'
+,DOCUMENT_ID,'document.pdf')") ;
my $SQL = "select url,document_id FROM $tablename where left(publish_d
+ate,6) ='$date'";
my $query = $dbh->prepare($SQL) or die "prepare: ".$dbh->errstr;
$query-> execute() or die "execute: ".$dbh->errstr;

while ($url,$document_id = $query->fetchrow_array()) {
   print "url: $row->{url} \n";
  

   my $outfile = '$path.$document_id';
   my $ff = File::Fetch->new( uri => url );
   $ff->fetch(to => $outfile) or die "failed to fetch '$url' to '$outf
+ile'.";
   #rename("document.pdf","/output/$document_id.pdf") || die "Can't re
+name file: ";
[download]

my $dbh = DBI->connect($dsn, $user, $password)
  or die "Couldn't connect to database: " . DBI->errstr;
[download]

Here you test that the connection has succeeded and bail out if it hasn't. This is good. However, on the subsequent 4 $dbh->do statements you make no such tests. How can you tell if one or more of these have failed?

my $SQL = "select url,document_id FROM $tablename where left(publish_d
+ate,6) ='$date'";
my $query = $dbh->prepare($SQL) or die "prepare: ".$dbh->errstr;
$query-> execute() or die "execute: ".$dbh->errstr;
[download]

No reason at all not to use a placeholder here:

my $SQL = "select url,document_id FROM $tablename where left(publish_d
+ate,6) = ?";
my $query = $dbh->prepare($SQL) or die "prepare: ".$dbh->errstr;
$query-> execute($date) or die "execute: ".$dbh->errstr;
[download]

it runs with no errors, it just doesn't download

Does it print the URL correctly each time through the loop or not?

---

🦛

However, on the subsequent 4 $dbh->do statements you make no such tests.

... and with a little bit of RTFM, none of those tests is needed. Change

my $dbh = DBI->connect($dsn, $user, $password)
  or die "Couldn't connect to database: " . DBI->errstr;
[download]

to

my $dbh = DBI->connect($dsn, $user, $password, { RaiseError => 1, Prin
+tError => 0 })
  or die "Couldn't connect to database: " . DBI->errstr;
[download]

and DBI will automatically check for errors, no manual checks needed.

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

you are right. it doesn't print the url. it just exits after printing url: But the table has the correct url in the field url.

so this is the code where there is an issue.

 
while ($url = $query->fetchrow_array()) {
   print "url: $row->{url}\n";
   # logic to get unique filename for output
     my $outfile = $path.$document_id;
   print $outfile;
   my $ff = File::Fetch->new( uri => url );
   $ff->fetch(to => $outfile) or die "failed to fetch '$url' to '$outf
+ile'.";
[download]