Retrieving a Single Field from a Table in PDO in PHP

Besides the fetch method, there is a special method fetchColumn, which allows you to get the value of a single column. Let's see what is meant.

First, let's prepare and execute a query. We will specify that we want to select only the name field:

<?php
	$res = $pdo->prepare('SELECT name FROM users');
	$res->execute();
?>

Let's get the results using the fetch method:

<?php
	while ($col = $res->fetch()) {
		var_dump($col);
	}
?>

As a result, in each iteration we will see an array consisting of one element - the user's name:

['name1']
['name2']
['name3']

Now let's apply fetchColumn:

<?php
	while ($col = $res->fetchColumn()) {
		var_dump($col);
	}
?>

As a result, in each iteration we will see the string with the user's name itself, not an array:

'name1'
'name2'
'name3'

Get the values of all user ages.