Generating Auto numbering based on

[Arnab Bhaumik]

I have a custom table where a field is there called "function" with different dropdowns (Marketing, Finance, etc) and another string field called "GAP ID". So my requirement is below : 

1. When a new record is created with Function "Finance" GAP ID will be autogenerated like: "FINI001a" where the 001 part will be auto-incremented for the next Finance function record.

2. When a new record is created with Function "Marketing" GAP ID will be autogenerated like: "MAR001a" where the 001 part will be auto-incremented for the next Marketing function record (002,003 etc). 

So I have tried with a before-insert business rule with the below details :

var now_GR = new GlideRecord('u_test_cmdb_table');

 now_GR.addEncodedQuery('u_function', current.u_function);

now_GR.orderBy('u_auto_id');

  now_GR.setLimit(1);  

  now_GR.query();

  if(now_GR.next()) {

    var newNum = now_GR.u_auto_id;

      var intg=newNum.slice(-3);

        var str= parseInt(intg);

      var str= str+1;

    var str1= str.toString();

    var str2= "00" + str1;

current.u_auto_id=str2;

current.update();

    }

But not working and giving undefined values and nothing is being updated.

[Bert_c1]

My test case is posted. change the "if" to "while" in line 6 from above, if more than one record matches the query, and remove line for with the 'setLimit()'.  So each record that meets the previous query is returned.