Best way to compare dates is probably to format them like YYYYMMDD. That way you can compare them numerically.

You can convert your date into this format like this:

$std_date = sprintf('%04d%02d%02d', 
                    (split m|/|, $date)[2, 1, 0]);
[download]

And I'm betting there's an Informix function that returns dates in a very similar format.

"Perl makes the fun jobs fun
and the boring jobs bearable" - me

I just wanted to point out that YYYYMMDD is also safe if you goof and compare it string-wise. That also makes it a great format for mixed data like "Mark20010106" since you can do the whole sort without an unpack/split/regex pass or heavy-duty transforming. Sexy...

--
$you = new YOU;
honk() if $you->love(perl)

I don't have experience with Informix; here's how it would look with DBI and Oracle, using TO_DATE to convert the string. This example looks for rows with a date_new column before 26/11/1987.

my $sth = $dbh->prepare(<<EndOfSQL);
  SELECT id
  FROM mytable
  WHERE date_new < TO_DATE(?, 'DD/MM/YYYY')
EndOfSQL

$sth->execute('26/11/1987');

while (my @row = $sth->fetchrow_array()) {
  print "@row\n";
}
[download]

I ++'ed this because he is absolutely right, about 90% of the time, you should be doing your date compares in SQL. Data in a DB should be tested in a DB whereever possible just to lower the amount of network traffic you impose on the system.

--
$you = new YOU;
honk() if $you->love(perl)