How to echo specific data in loop with a condition specific to the last row

Question

For an accounting system, I'm using PHP & MySQL. I've two tables "GROUP" and "ACHEADS".

In the GROUP table, I have:

---------------------
| id (AI) |  group  |
---------------------
|    1    | Group 1 |
|    2    | Group 2 |
---------------------

In the ACHEADS table, I have:

-----------------------------------------
| id (AI) |  ac_head    | amount | j_id |
-----------------------------------------
|    1    | Something 1 |  2000  |   1  |
|    2    | Something 2 |  1000  |   1  |
|    3    | Something 3 |  5000  |   2  |
|    4    | Something 4 |  4000  |   2  |
|    5    | Something 5 |  8000  |   2  |
-----------------------------------------

I've joined the two tables as GROUP.id <<->> ACHEADS.j_id

Now I need to preview the data like this:

----------------------------------------------
Particulars               | Details | Total  |
----------------------------------------------
Group 1                   |         |        |
 Something 1              |    2000 |        |
 Something 2              |    1000 |   3000 |
----------------------------------------------
Group 2                   |         |        |
 Something 3              |    5000 |        |
 Something 4              |    4000 |        |
 Something 5              |    8000 |  17000 |
----------------------------------------------
GRAND TOTAL               |         |  20000 |
------------------------------------==========

Challenges

1. The table will be dynamic and will generate within a PHP loop (I'm using a WHILE loop)
2. Remember: it's a table and if I miss echoing a td, then the table will break up

Problems

• When I'm using the loop it's echoing the data on the Details td accurately. But the sum of the details row according to j_id is also echoing in each td

Preview here:

----------------------------------------------
Particulars               | Details | Total  |
----------------------------------------------
Group 1                   |         |        |
 Something 1              |    2000 |   3000 |
 Something 2              |    1000 |   3000 |
----------------------------------------------
Group 2                   |         |        |
 Something 3              |    5000 |  17000 |
 Something 4              |    4000 |  17000 |
 Something 5              |    8000 |  17000 |
----------------------------------------------

My thoughts

• If I can check whether it is the last data of the query, if isset, then echo the total amount with it's td. (But remember the Challenge#2)
• Does it require a foreach loop?

I failed

• I tried checking max(id), it works fine in SQL, but can't use it in condition within a loop.

(If you still can't understand me, then on the second phase, I'll post my code.)

Answer 1

I would do 2 loops:

1. Fetch id from GROUP
2. Fetch amount from ACHEADS based on j_id

This would look something like (non-tested code):

echo '<table><tr><td>Particulars</td><td>Details</td><td>Total</td></tr>';

$total = 0;

$q1 = "SELECT id FROM `GROUP`";
$res1 = mysqli_query($q1);
while($row1 = mysqli_fetch_assoc($res1)) {
    echo 

    $group_total = 0;
    $j_id = $row1[id];

    $q2 = "SELECT ac_head, amount FROM ACHEADS WHERE j_id = $j_id";
    $res2 = mysqli_query($q2);
    while($row2 = mysqli_fetch_assoc($res1)) {

        echo '<tr><td>' . $row2[ac_head] . '</td>';
        echo '<td>' . $row2[amount] . '</td></tr>';

        $group_total = $group_total + $row2[amount];
        $total = $total + $row[amount];
    }

   echo '<tr><td colspan="3" align="right">' . $group_total . '</td></tr>';
}

echo '<tr><td>GRAND TOTAL</td>';
echo '<td colspan="2" align="right">' . $total . '</td></tr>';
echo "</table>";