题目: 题解:
class Solution {
public:int getSum(int a, int b) {while (b ! 0) {unsigned int carry (unsigned int)(a & b) << 1;a a ^ b;b carry;}return a;}
};
目录 一、联合索引失效场景二、哪一个字段使用到了联合索引三、根据sql如何建立联合索引 一、联合索引失效场景
1、对(a,b,c)创建联合索引
where b2where c3where b2 and c3
以上场景均在在a无序的情况下b、c无法有序
where b2 and a4where b2 and c…