Question

I once read in a performance blog that it is better to use PHP’s date functions to set dates in a MySQL query instead of using mysql date functions like curdate() because mysql can then cache the query or the result or something like that. Does anyone have any insight into this? Does it hold any water or is it baseless?

example:

$query = 'SELECT id FROM table WHERE publish_date = \''.date('Y-m-d').'\'';

vs

$query = 'SELECT id FROM table WHERE publish_date = CURDATE()';

Answer 1

Any function containing CURDATE() will not be cached. Source

Hardcoding the date should still be cached as far as I can tell. Though you might want to consider using the prepare functionality instead of splicing strings into your query (for sanity and security sake).