All Rows from Result in PDO in PHP

You can immediately get an array of all rows from the query result. This is done using the fetchAll method. Let's look at the different modes of operation of this method. All examples will be for the test table.

Getting a Simple Array

Let's apply the fetchAll method to get a simple data array. To do this, we leave the method parameters empty:

<?php
	$res = $pdo->query('SELECT * FROM users');
	
	$row = $res->fetchAll();
	var_dump($row);
?>

Code execution result:

[
	[
		'id'     => 1,
		'name'   => 'name1',
		'age'    => 21,
		'salary' => 500,
	],
	[
		'id'     => 2,
		'name'   => 'name2',
		'age'    => 22,
		'salary' => 600,
	],
	[
		'id'     => 3,
		'name'   => 'name3',
		'age'    => 23,
		'salary' => 600,
	],
	[
		'id'     => 4,
		'name'   => 'name4',
		'age'    => 24,
		'salary' => 700,
	],
	[
		'id'     => 5,
		'name'   => 'name5',
		'age'    => 25,
		'salary' => 800,
	],
]

Getting a Single Column

Let's get only one column from the table. To do this, pass the FETCH_COLUMN parameter to the fetchAll method:

<?php
	$res = $pdo->query('SELECT name FROM users');
	
	$row = $res->fetchAll(PDO::FETCH_COLUMN);
	var_dump($row);
?>

Code execution result:

[
	'name1',
	'name2',
	'name3',
	'name4',
	'name5',
]

Getting a Key-Value Pair

Let's get the data in the form of a key-value pair, where the key will be the id, and the value will be the user's name. To do this, pass the FETCH_KEY_PAIR mode as a parameter to the fetchAll method:

<?php
	$res = $pdo->query('SELECT id, name FROM users');
	
	$row = $res->fetchAll(PDO::FETCH_KEY_PAIR);
	var_dump($row);
?>

Code execution result:

[
	1 => 'name1',
	2 => 'name2',
	3 => 'name3',
	4 => 'name4',
	5 => 'name5',
]

Getting Records with a Unique Field

You can make it so that a unique field (generally this is id) becomes the key for each subarray:

<?php
	$res = $pdo->query('SELECT * FROM users');
	
	$row = $res->fetchAll(PDO::FETCH_UNIQUE);
	var_dump($row);
?>

Code execution result:

[
	1 => [
		'id'     => 1,
		'name'   => 'name1',
		'age'    => 21,
		'salary' => 500,
	],
	2 => [
		'id'     => 2,
		'name'   => 'name2',
		'age'    => 22,
		'salary' => 600,
	],
	3 => [
		'id'     => 3,
		'name'   => 'name3',
		'age'    => 23,
		'salary' => 600,
	],
	4 => [
		'id'     => 4,
		'name'   => 'name4',
		'age'    => 24,
		'salary' => 700,
	],
	5 => [
		'id'     => 5,
		'name'   => 'name5',
		'age'    => 25,
		'salary' => 800,
	],
]

Practical Tasks

Display all users from the users table, using the method described in the lesson.

Display one row of data from the users table.

Display the name and age of users as a key-value pair.