Auto detect number of same entry and do a rowspan according to the number?

i wanted to create a forloop which will create a table from the data obtained from the database.

the obtained result looks something like this.

id/cart_id/title/price/quantity
1 / 1     /book1/10.00/ 2
2 / 1     /book2/19.00/ 1

In the for loop its normal to create 2 tab开发者_如何转开发le row to hold these 2 results. However i want one of the to rowspan and show only cart_id "1" once.

this is my current code

<?php
                for($i = 0; $i < count($history); $i++) {
                    $a = $history[$i]['cart_id'];
                    echo '<tr >';
                    if($history[$i]['cart_id'] == $history[$i]['cart_id']){                     
                    echo '<td rowspan="2">'.$a.'</td>';
                    }
                    echo '<td>'.$history[$i]['title'].'</td>';
                    echo '<td>'.$history[$i]['price'].'</td>';
                    echo '<td>'.$history[$i]['quantity'].'</td>';
                    echo '<td>'.$history[$i]['cart_id'].'</td>';
                    echo '</tr>';
                }
                ?>

edit

original output:
[id:1][book1][19.90][2]
[id:1][book2][10.90][1]

what i wanted: The id row will rowspan according to the number of same ID.Thus showing ony 1 "id:1"

[    ][book1][19.90][2]
[id:1][book2][10.90][1]

How is it possible to achieve what i want?

You can achieve this with an extra for loop:

<?php
    $lastcart = FALSE ;
    for($i = 0; $i < count($history); $i++) {
        $a = $history[$i]['cart_id'];
        echo '<tr >';
        $rowspan = 0;
        for(
            $j=$i;
            $history[$i]['cart_id'] !== $lastcart &&
            $j < count($history) && 
            $history[$j]['cart_id']==$history[$i]['cart_id'];
            $j++
        ){
            $rowspan++ ;
        }
        if($rowspan > 0){
            $lastcart = $history[$i]['cart_id'] ;
            echo '<td rowspan="{$rowspan}">'.$a.'</td>';
        }
        echo '<td>'.$history[$i]['title'].'</td>';
        echo '<td>'.$history[$i]['price'].'</td>';
        echo '<td>'.$history[$i]['quantity'].'</td>';
        echo '<td>'.$history[$i]['cart_id'].'</td>';
        echo '</tr>';
    }
?>