> Learn your DB server. Check the query plans often. You might get surprised. Tweak and recheck. Oftentimes the well-designed queries behave unexpectedly, beca

> Learn your DB server. Check the query plans often. You might get surprised. Tweak and recheck. Oftentimes the well-designed queries behave unexpectedly, because the column statistics are not updated or when the data is fragmented for big tables (e.g. random PK insertion).