What are some common pitfalls to avoid when working with MySQL queries in PHP to prevent errors like the one experienced by the forum user?

The common pitfall to avoid when working with MySQL queries in PHP is not properly escaping user input, which can lead to SQL injection attacks. To prevent this, always use prepared statements with parameterized queries to securely pass user input to the database. 

// Example code snippet using prepared statements to prevent SQL injection
$mysqli = new mysqli("localhost", "username", "password", "database");

// Check connection
if ($mysqli->connect_error) {
    die("Connection failed: " . $mysqli->connect_error);
}

// Prepare a SQL query using a placeholder for the user input
$stmt = $mysqli->prepare("SELECT * FROM users WHERE username = ?");
$stmt->bind_param("s", $username);

// Set the user input and execute the query
$username = $_POST['username'];
$stmt->execute();

// Process the results
$result = $stmt->get_result();
while ($row = $result->fetch_assoc()) {
    // Do something with the data
}

// Close the statement and connection
$stmt->close();
$mysqli->close();

Keywords

MySQL queries PHP error handling SQL injection prepared statements

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