- array_merge: documentation ( source)
- implode: documentation ( source)
<?php
$input = array(
array(
'tag_name' => 'google'
),
array(
'tag_name' => 'technology'
)
);
//$letters = array();
foreach ($array as $value) {
$input = array_merge($array, $value["tag_name"]);
}
echo implode(', ', $letters);
//$ids = array_column($input, 'tag_name');
//$output = implode(',', $ids);