PHP PDO Query Guide: Secure Data Retrieval

When querying data using PDO, you can follow these steps:

1. Connect to the database.

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "database_name";

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "Connected successfully";
} catch(PDOException $e) {
    echo "Connection failed: " . $e->getMessage();
}

1. Write SQL query:

$sql = "SELECT * FROM table_name";

1. Prepare and execute the query statement.

$stmt = $conn->prepare($sql);
$stmt->execute();

1. Obtain search results:

$result = $stmt->fetchAll(PDO::FETCH_ASSOC);

1. Handle search results:

foreach($result as $row) {
    echo $row['column_name'];
}

The complete example code is as follows:

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "database_name";

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "Connected successfully";

    $sql = "SELECT * FROM table_name";
    $stmt = $conn->prepare($sql);
    $stmt->execute();
    $result = $stmt->fetchAll(PDO::FETCH_ASSOC);

    foreach($result as $row) {
        echo $row['column_name'];
    }
} catch(PDOException $e) {
    echo "Connection failed: " . $e->getMessage();
}

Please replace $servername, $username, $password, and $dbname with the actual database connection information. Also, replace table_name and column_name with the real table name and column name.