There are a few issues with your post:

• It would help if you provide SHORT, RUNNBLE CODE that demonstrates the issue
• It would help if code were indented properly - that would allow others to see loop boundaries
• You have misunderstood how to process the return value from fetchall_arrayref
• You have a syntax error in "while ( $status eq 'PAID') ) {"
• Your "redo" will not work the way you seem to expect

Please try to understand and use standard perl "idioms" - they help make code more understandable and avoid bugs.

Here is an idiomatic flow for your case:

my $query = $dbh->prepare("SELECT ordernumber FROM orders ORDER BY cre
+ated ASC");  
$query->execute();

####### FUNCATION (A)
while( my $row = $query->fetchrow_arrayref() )
{
    my $ordernumber = $row->[0]; # First, and only  field in returned 
+list
   
    # WHEN I PRINT THE OUTPUT IS
   
    #  545455
    #  745454
    #  645450


    # NOW I WANT TO CHECK EACH ORDER NUMBER VIA LINK
    # ITS LIKE I WANT TO RUN HTTP REQUEST FOR EACH ORDER NUMBER

    my $url = "LINK/$ordernumber";
        print "URL: $url\n";
    my $req = HTTP::Request->new(GET=>$url);
    my $resp = $ua->request($req);
    my $response = JSON::XS->new->decode ($resp->content);
    my $status = $response->{status};
        # WHILE WE GET ORDER NUMBER WITH MATCHING RESLUTS
    while ( $status eq 'PAID')  {
      #// DO STAFFS HERE
      #// WHEN DONE THEN KEEP CHECKING OTHER ORDER NUMBER USING REDO
    }
    #no redo;  # REDO FUNCATION (A) AFTER SUCCESS - ITS LIKE RESTART T
+HE WHOLE FUNCATION AGAIN
           # BEACUSE AFTER SUCCESS, I HAVE TO KEEP ALSO CHECKING REAMI
+NING ORDER NUMBER STATUES
}
$dbh->disconnect();
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