So curiosity got to me. I always try to avoid creating variables that will only be used once, instead I try to use it directly (unless it's a lot of text, for example MySQL queries).
What I usually do is something like this:
$getSomethingSql = 'LONG SQL';
$getSomething = $dbConnection->prepare($getSomethingSql); // or query if no parameters are needed
// Some binds etc if needed
$getSomething->execute(); // if prepared statements are used
$something = $getSomething->fetchAll(PDO::FETCH_ASSOC);
foreach ($something as $s) {}
Now, the $getSomethingSql is only used once but is stored as a variable since it can be a long string and thus this looks better. However, I was curious if there is any advantage of using above versus the code below:
$getSomethingSql = 'LONG SQL';
$getSomething = $dbConnection->prepare($getSomethingSql); // or query if no parameters are needed
// Some binds etc if needed
$getSomething->execute(); // if prepared statements are used
foreach ($getSomething->fetchAll(PDO::FETCH_ASSOC) as $s) {}
Does these 2 codes do the same? And is there a (huge) performance difference, or is one of them cleaner?
Internally they'll do the same thing. The only difference is that in one case it will use your explicitly created variable to hold the results of fetchAll() and in the second case it will make use of a temporary variable.