Question

This is a pretty simple question and I’m assuming the answer is “It doesn’t matter” but I have to ask anyway…

I have a generic sql statement built in PHP:

$sql = 'SELECT * FROM `users` WHERE `id` IN(' . implode(', ', $object_ids) . ')';

Assuming prior validity checks ($object_ids is an array with at least 1 item and all numeric values), should I do the following instead?

if(count($object_ids) == 1) {
    $sql = 'SELECT * FROM `users` WHERE `id` = ' . array_shift($object_ids);
} else {
    $sql = 'SELECT * FROM `users` WHERE `id` IN(' . implode(', ', $object_ids) . ')';
}

Or is the overhead of checking count($object_ids) not worth what would be saved in the actual sql statement (if any at all)?

Answer 1

Neither of them really matter in the big scope of things. The network latency in communicating with the database will far outweigh either the count($object_ids) overhead or the = vs IN overhead. I would call this a case of premature optimization.

You should profile and load-test your application to learn where the real bottlenecks are.