了解&& r.RateList2在这里

&& ->向WHERE子句添加多个条件
r.RateList2->看起来r对象具有这样的实现.这是一个可供使用的属性.

understand what the && r.RateList2 is doing here

&& -> Adding multiple condition to WHERE clause
r.RateList2 -> looks like r object has such implementation. It''s a property exposed to be used.