hi i am new in perl and i am trying to query a table in oracle db. I would like for help in debgging my script. I've tried executing the same SQL statement in TOAD and it works just fine, but when I try to execute it using perl no rows are being returned. Below is the code

$SQL = "SELECT $columns FROM $tbl WHERE $col_cond $val_cond AND $date_col <= SYSDATE - NUMTODSINTERVAL($ll,'HOUR') AND $date_col >= SYSDATE - NUMTODSINTERVAL($ul,'HOUR')";

my $sth = $dbh->prepare($SQL) or die "prepare failed: ". $dbh->errstr();

while (row = $sth->fetchrow())
$line = join(",", row), "\n";
print "$line\n";

Thank you in advance for the help