Number each nested table inside a master table on a Jasper report - jasper-reports

Question

So i have the following issue. In my database I have a table named
bp_minutes_app.
This table stores records of minutes from committee meetings. Each minute can consist of many files. The database design regarding minutes is the following:
The table bp_minutes_attachments is connected via a foreign key to the bp_minutes_app and holds the following information:
description, createdby
The table
bp_files
is connected via a foreign key to the
bp_minutes_app
and holds the file along other information. We are interested in taking only the name and id of the file (the latter in order to create a hyperlink to the file, but this is out of scope of the present question).
Final remark. All those tables are linked to the master
bp_full
table that is joined only to get the id of each specific report.
In my report I want to print on a table all minutes and the accompanying information (file name, description, createdby, submission date), but make a separate entry for each minute. In order to achieve this, I first created a table that uses the following dataset:
SELECT bp_minutes_app.id
FROM bp_minutes_app
INNER JOIN bp_full ON
bp_minutes_app.bp_full_app_id = bp_full.id
WHERE bp_full.id = $P{id}
With this dataset I retrieve each minutes record. In my example, I get two records with ids 39 and 40.
Inside this table I nested another table to retrieve information for each file in each minutes record. The dataset that I used is the following:
SELECT bp_minutes_app.submission_date,
bp_minutes_attachments.createdby,
bp_minutes_attachments.description,
bp_files.id,
bp_files.name
FROM bp_minutes_attachments
left JOIN bp_minutes_app ON
bp_minutes_attachments.bp_minutes_app_id = bp_minutes_app.id
AND bp_minutes_app.id = $P{mid}
left JOIN bp_full ON
bp_minutes_app.bp_full_app_id = bp_full.id
left JOIN bp_files ON
bp_minutes_attachments.bp_file_id = bp_files.id
WHERE
bp_full.id = $P{id}
The id parameter is used again to take the specific report and the mid parameter to take a specific minute. On parameter specification mid is declared as follows:
mid = $F{id}
, where id is the bp_minutes_app.id.
Following this setup I managed to get nested tables for each minute (forgive me for the greek headers):
What I want to do is number each subtable from 1...n, according to the number of minutes/ subtables. How can I achieve this? I tried to create a suitable variable but it was not met with success. I want to somehow "save" in a parameter / variable the count of bp_minutes_app records and manipulate this number for each nested table header, instead of just numbering each table with the corresponding id.
Sorry for the long post but I am new to Jasper and I wanted to be clear about the steps I have taken and what I want to achieve.

Answer 1

Alot of sql not much jrxml in your post so I start by guessing.
Have you tried something like this in the jrxml:
<variable name="counter" class="java.lang.Integer" calculation="Count">
<variableExpression><![CDATA[$F{id}]]></variableExpression>
</variable>