What are common errors when trying to fetch data from a database using PHP?

Common errors when trying to fetch data from a database using PHP include not connecting to the database, using incorrect SQL syntax, and not handling errors properly. To solve these issues, make sure to establish a connection to the database using the appropriate credentials, double-check your SQL queries for accuracy, and implement error handling to catch any potential issues that may arise during the data retrieval process. 

// Establish a connection to the database
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// Fetch data from the database using a SQL query
$sql = "SELECT * FROM table_name";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // Output data from each row
    while($row = $result->fetch_assoc()) {
        echo "Column1: " . $row["column1"]. " - Column2: " . $row["column2"]. "<br>";
    }
} else {
    echo "0 results";
}

// Close the database connection
$conn->close();

Keywords

SQL injection PDO mysqli error handling data validation

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