Question

I have a requirement, where request_id will be in the form of
REQ0000001,REQ0000002....REQ0000010, REQ0000011...., REQ0000099 REQ0000100..... like first three char is REQ followed by 7 characters (number is sequence)… this request_id is the primary key in mysql table.

suppose last entry in table is REQ0000009, next entry wil be REQ0000010.. How to do it in perl??

I am using the following way:

$sql_query = "select request_id from requests order by request_id DESC LIMIT 1";

store this value in varibale named x. then

$x = reverse $x;  #Reverse the String
chop $x; # Chop the last Character (here R)

chop $x; # Chop the last Character (here E)

chop $x; # Chop the last Character (here Q)

$x = reverse $x; # Again Reverse
$x = $x  + 1; # Add 1

if ( length($x) eq 1) # if length ==1{

    $NextReq_id = 'REQ000000'.$x;

elsif ( length($x) eq 2)


    $NextReq_id = 'REQ00000'.$x;

elsif ( length($x) eq 3)


    $NextReq_id = 'REQ0000'.$x;

elsif ( length($x) eq 4)
{

$NextReq_id = 'REQ000'.$x;
} 

Is here any better way to do this?

Answer 1

$sql_query = "SELECT CONCAT('REQ',LPAD(CAST(SUBSTR(request_id,4,7) AS UNSIGNED)+1,7,'0')) ORDER BY request_id DESC LIMIT 1"