What are some common pitfalls when embedding complex MySQL queries in PHP?

One common pitfall when embedding complex MySQL queries in PHP is failing to properly sanitize user input, which can lead to SQL injection attacks. To prevent this, always use prepared statements with parameterized queries to safely execute SQL commands. 

// Example of using prepared statements to safely execute a complex MySQL query in PHP

// Establish a connection to the database
$pdo = new PDO('mysql:host=localhost;dbname=mydatabase', 'username', 'password');

// Prepare the SQL query with placeholders for parameters
$stmt = $pdo->prepare('SELECT * FROM users WHERE username = :username AND email = :email');

// Bind the parameters to the placeholders
$stmt->bindParam(':username', $username);
$stmt->bindParam(':email', $email);

// Execute the query
$stmt->execute();

// Fetch the results
$results = $stmt->fetchAll();

// Loop through the results and do something with them
foreach ($results as $row) {
    // Do something with each row
}

// Close the connection
$pdo = null;

Keywords

MySQL PHP SQL injection prepared statements error handling

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