What are some common pitfalls when using JOIN in PHP?

Common pitfalls when using JOIN in PHP include forgetting to specify the join condition, resulting in a Cartesian product, and not properly handling NULL values in the joined columns. To avoid these issues, always specify the join condition explicitly and handle NULL values appropriately in your queries. 

// Example of a correct JOIN query in PHP
$query = "SELECT users.username, orders.order_id
          FROM users
          JOIN orders ON users.user_id = orders.user_id";
$result = mysqli_query($connection, $query);

Keywords

JOIN SQL database performance optimization

Related Questions