How to do an inner loop of records in php

问题

I am learning PHP and I want to know how to do an inner loop or nested loop with records in PHP. I will appreciate if somebody explains me how to do this type of loop in PHP.

I have this table in MySQL [

]

I just want to create a report table in PHP that looks like this:

So far, I know how to do a current loop with the code below but how could I do in the same loop and inner loop to show dishes like table above. I know how to create the format (table, spaces, etc) I just need the PHP logic to do this in the best way.

<?php  
do {  ?>
Table in here
 <?php } while ($selecc =    mysqli_fetch_assoc($conmenu));  ?>

回答1:

The clean/direct approach should be something like this:

SELECT Client, Option, GROUP_CONCAT(Dish SEPARATOR ', ')
FROM table_name
GROUP BY Client, Option

Then with your data already grouped and glued together, just print your strings in a single loop of the result set.

Using a do {} while () is of no benefit here.

Here's an untested snippet...

if ($conmenu) {
    echo '<table>';
        echo '<tr><td>Client</td><td>Option</td><td>Dishes</td></tr>';
        while ($row = mysqli_fetch_assoc($conmenu)) {
            echo '<tr><td>' , implode('</td><td>', $row) , '</td></tr>';
        }
    echo '</table>';
}

For the record:

The maximum permitted result length in bytes for the GROUP_CONCAT() function. The default is 1024.

https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_group_concat_max_len

Also, $conmenu is iterable, so you could use a foreach instead of a while loop.

foreach ($conmenu as $row) { ...

If you want to do it the hard way...

SELECT Client, Option, Dish
FROM table_name
ORDER BY Client, Option

Then... (untested)

if ($conmenu) {
    echo '<table>';
        echo '<tr><td>Client</td><td>Option</td><td>Dishes</td></tr>';

        $group = null;
        foreach ($conmenu as $row) {
            if ($group !== $row['Client'] . '_' . $row['Option']) {
                if ($group !== null) {
                    echo '</td></tr>';
                }
                echo '<tr><td>' , implode('</td><td>', $row);
            } else {
                echo ", " , $row['Dish'];
            }
            $group = $row['Client'] . '_' . $row['Option'];  // update group
        }
        echo '</td></tr>';  // close final iteration
    echo '</table>';
}

来源：https://stackoverflow.com/questions/54204805/how-to-do-an-inner-loop-of-records-in-php

标签

php

nested-loops