I can get your exact code to save but it returns nothing.
I’ve tried this:
SELECT * FROM 40e_postmeta WHERE post_author=1 && post_date BETWEEN “<?php $_GET[date_from]; ?>” AND “<?php $_GET[date_to]; ?>”
and get this error:
Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ”’” AND ”’ at line 1