Extracting columns from sql table with php - php

Question

My query selects all columns from my table
$spool = $wpdb->get_results('SELECT * FROM `tablename`');
then I display the results in a table. I need to display all columns. This is the way I do it.
echo "<table>";
if ( !empty( $spool ) ) {
echo "<tr><th> header </th></tr>";
foreach ( $spool as $a ) {
echo "<tr><th>" . $a->columnname1 . "</th><th>" .$a->columnnameN . "</th></tr>";
}
}
echo "</table>";
Now since I have around 40 columns, I'd like to ask if there is a more intelligent and less tedious way of displaying them.

Answer 1

probably you need nested loops, you are getting result probably like this
array(
0:{column1:test,column2:test . . . },
1:{column1:test,column2:test . . . }
)
so you can try this way
echo "<table>";
if ( !empty( $spool ) ) {
echo "<tr><th> header </th></tr>";
foreach ( $spool as $key => $value ) {
echo '<tr>';
foreach ( $value as $a ) {
echo "<th>" . $a. "</th>";
}
echo '</tr>';
}
}
echo "</table>";

Answer 2

As you have objects you could cast them to arrays and use implode.
(But attribute order could be different from what you want.)
<?php
class A
{
public $foo = 'bing';
public $bar = 'bang';
public $baz = 'bong';
}
$spool = [new A, new A];
echo '<table>';
foreach($spool as $a) {
echo '<tr>';
echo '<td>' . implode('</td><td>', (array) $a) . '</td>';
echo '</tr>';
}
echo '</table>';
Output:
<table><tr><td>bing</td><td>bang</td><td>bong</td></tr><tr><td>bing</td><td>bang</td><td>bong</td></tr></table>