What are some best practices for optimizing PHP code that involves querying multiple tables?

When querying multiple tables in PHP, it is important to optimize the code to ensure efficient performance. One best practice is to use JOIN clauses in SQL queries to combine data from multiple tables in a single query, rather than making separate queries for each table. Additionally, consider using indexes on the columns being queried to improve query performance. Lastly, limit the data being retrieved by only selecting the necessary columns and rows to reduce the amount of data being processed.

// Example of optimizing PHP code for querying multiple tables using JOIN clauses
$query = "SELECT users.name, orders.order_date, products.product_name 
          FROM users 
          JOIN orders ON users.id = orders.user_id 
          JOIN products ON orders.product_id = products.id 
          WHERE users.id = 1";

$result = mysqli_query($connection, $query);

if ($result) {
    while ($row = mysqli_fetch_assoc($result)) {
        // Process the data retrieved from the query
    }
} else {
    echo "Error: " . mysqli_error($connection);
}