See Regular Expressions perlre

#!perl
use DBI;
use strict;
my $dbh = get_dbh(); # connect to db

# build regex
my @keyword = qw(www http .com);
my $words = join '|',@keyword;
my $regexp = qr/$words/i;
print "Regular Expression is $regexp\n";

# search for key words
my $sql = 'SELECT comment_ID,comment_content 
           FROM wp_comments';
           
my $sth = $dbh->prepare($sql);
$sth->execute();

my @spam = ();
while (my ($id,$content) = $sth->fetchrow_array()) {
  if ($content =~ /$regexp/ ){
    print "ID :  $id\ncomment : $content\n\n";
    push @spam,$id;
  }  
}

# delete records
my $sql_del = 'DELETE FROM wp_comments
               WHERE comment_ID = ?';

my $sth_del = $dbh->prepare($sql_del);
for my $id (@spam){
  # enable this when you are sure it's working !!
  #$sth->execute($id); 
  print "Deleted $id\n";
}
[download]

poj