What potential pitfalls should be considered when using complex SQL queries in PHP applications?

When using complex SQL queries in PHP applications, potential pitfalls to consider include increased complexity, difficulty in debugging, and vulnerability to SQL injection attacks. To mitigate these risks, it is recommended to break down complex queries into smaller, more manageable parts, use prepared statements to prevent SQL injection, and implement proper error handling to catch and address any issues that may arise. 

// Example of using prepared statements with PDO to execute a complex SQL query safely

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

// Prepare the SQL query with placeholders
$stmt = $pdo->prepare("SELECT * FROM users WHERE age > :age AND gender = :gender");

// Bind parameter values to the placeholders
$stmt->bindParam(':age', $age, PDO::PARAM_INT);
$stmt->bindParam(':gender', $gender, PDO::PARAM_STR);

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

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

// Loop through the results
foreach ($results as $row) {
    echo $row['name'] . "<br>";
}

// Close the connection
$pdo = null;

Keywords

SQL injection performance data integrity error handling query optimization

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