Hey, i have tried your solution but it is not working. Not printing while loop statements.

my $dbh = DBI->connect("DBI:DB2:xxx",'xxx','xxx',{ RaiseError => 0, Au
+toCommit => 1 })
or die ("Could not connect to database :".DBI->errstr);

my %hash =
(
'2017-01-01 00:00:00' => '2017-01-31 00:00:00',
'2017-02-01 00:00:00' => '2017-02-28 00:00:00',
'2017-03-01 00:00:00' => '2017-03-31 00:00:00',
'2017-04-01 00:00:00' => '2017-04-30 00:00:00',
'2017-05-01 00:00:00' => '2017-05-31 00:00:00',
'2017-06-01 00:00:00' => '2017-06-30 00:00:00',
'2017-07-01 00:00:00' => '2017-07-31 00:00:00',
'2017-08-01 00:00:00' => '2017-08-31 00:00:00',
'2017-09-01 00:00:00' => '2017-09-30 00:00:00'
);

#open(my $fh , "+>/var/www/bin/filesample.txt");

foreach my $key(sort keys %hash) {
chomp($key);
my $sql = "select distinct FID_CUST from session where DAT_END between
+ ? and ?";
chomp($sql);
#print "\$sql = $sql\n";

my $sth = $dbh->prepare($sql);
$sth->execute($key,$hash{$key}) or die "Couldn't execute statement: $D
+BI::errstr";
print "sth: $sth\n";

while (my $arr = $sth->fetchrow_arrayref()){
print "in while\n";
print "@$arr\n";
        }
$sth->finish();
}
#close FH;
$dbh->disconnect;
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