When using DBI and prepare, use placeholders. If you don't know what they are, read the doc. To put it simply, you can put a ? in the prepare statement, pass values for each in the execute, and it will properly quote it for you. In your case, something like this

my $dbh = $db->prepare("SELECT balance FROM Table1 WHERE username=? an
+d balance < '-.01'");
$dbh->execute($authuser);
my ($balance_due) = $dbh->fetchrow_array;
[download]

Anyway, the easiest solution to your problem would be to simply negate the value, which would yield a positive. So something like

$balance_due = -$balance_due

# or

$balance_due = $balance_due * -1;
[download]

To answer your question using a different way, you could also use a substitution regex

$balance_due =~ s/-//;
[download]

Added Second paragraph.

Actually, I think it would be better to just get the absolute value:

$balance_due = abs($balance_due);
[download]

This protects you in the event that $balance_due is a positive number (which shouldn't happen according to the SQL, but I've always beleived that a good programmer is someone who looks both ways on a one way street). It's also close enough in speed to negation that random noise is a factor in execution time. Code:

#!/usr/bin/perl
use strict;
use warnings;
use Benchmark qw(cmpthese);

my $data  = -12345;
my $count = pop || 500000;

cmpthese($count, {
    negate   => sub { my $i = -$data }, 
    absolute => sub { my $i = abs($data) }, 
    regex    => sub { my ($i) = $data =~ s/-// }, 
});
[download]

Results:

Benchmark: timing 500000 iterations of absolute, negate, regex...
  absolute:  1 wallclock secs ( 1.24 usr +  0.00 sys =  1.24 CPU) @ 40
+4858.30/s (n=500000)
    negate:  1 wallclock secs ( 1.15 usr +  0.00 sys =  1.15 CPU) @ 43
+3275.56/s (n=500000)
     regex:  3 wallclock secs ( 3.16 usr +  0.00 sys =  3.16 CPU) @ 15
+8328.06/s (n=500000)
             Rate    regex absolute   negate
regex    158328/s       --     -61%     -63%
absolute 404858/s     156%       --      -7%
negate   433276/s     174%       7%       --
[download]

----
I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

Note: All code is untested, unless otherwise stated

++, you're absolutely right. When writing up my node, I forgot all about just getting the absolute value. ; )

Works like a charm! You guys are awesome! Thanks for your prompt reply! Regards, -Paul

• You can take the negative of the value in the sql...

  $dbh=$db->prepare("SELECT -balance FROM Table1 
                     WHERE  username='$authuser' 
                            and balance < '-.01'");
  $dbh->execute();
  ($balance_due) = $dbh->fetchrow_array();
  [download]

• You can take the negative of the value in the perl...

  $dbh=$db->prepare("SELECT -balance FROM Table1 
                     WHERE  username='$authuser' 
                            and balance < '-.01'");
  $dbh->execute();
  ($tmp) = $dbh->fetchrow_array();
  $balance_due = 0 - $tmp;
  [download]

• You can use substr to strip out the first character...

  $dbh=$db->prepare("SELECT -balance FROM Table1 
                     WHERE  username='$authuser' 
                            and balance < '-.01'");
  $dbh->execute();
  ($tmp) = $dbh->fetchrow_array();
  $balance_due = substr $tmp, 1;
  [download]

Thanks again! -p

There are quite a ways to drop the -ve sign...

my $due = -9.98;

printf "substr_idx: %s\nneg_one_mul: %s\nregex: %s\n"
  , substr_idx($due)
  , neg_one_mul($due)
  , regex($due);

sub substr_idx
{ my $number = shift;
  return
    -1 < index($number , '-' , 0)
    ? substr($number , 1)
    : $number;
}

sub neg_one_mul
{ my $number = shift;
  return
    $number =~ m/^-/
    ? $number * -1
    : $number;
}

sub regex
{ my $number = shift;
  return
    $number =~ m/^- (.+)/x
    ? $1
    : $number;
}
[download]

...Whatever you do just do not try to compare a floating point number (-9.98) against an integer (0) (or another float) -- due to inherent error in number representation -- w/o using some minimum difference that you would treat to be same as zero.

my $val = -9.99;
print abs $val
__OUTPUT__
9.99
[download]

--

flounder