How to Retrieve Single Database Values Efficiently with PHP PDO's fetchColumn()?

Retrieving Single Database Values Effectively with PHP PDO

To fetch a single value from a database column in PHP using PDO, one can employ a more efficient approach. Instead of a loop or multiple queries, consider using the fetchColumn() method.

The following code demonstrates how to use fetchColumn():

<?php
try {
    $conn = new PDO('mysql:host=localhost;dbname=advlou_test', 'advlou_wh', 'advlou_wh');
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch(PDOException $e) {
    echo 'ERROR: ' . $e->getMessage();
}

$userid = 1;

$q= $conn->prepare("SELECT name FROM `login_users` WHERE username=?");
$q->execute([$userid]);
$username = $q->fetchColumn();

echo $username;
?>

In this code:

1. A PDO connection is established.
2. A prepared statement is created using prepare().
3. The statement is executed using execute() with the appropriate parameter.
4. Finally, fetchColumn() is employed to retrieve the single value from the specified column.

This streamlined approach reduces the code complexity and improves performance compared to using multiple queries or loops.

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