left join 语句如何优化？

Question

SELECT u.id,u.name,u.mobile,u.regtime,f.yqruid FROM ym_juser as u LEFT JOIN ym_friend as f ON u.id=f.reguid WHERE u.regtime>1510761600 AND u.regtime < 1511280000 ORDER BY f.yuid asc

Answer 1

把条件查询放到子查询中。