MySQL索引面试题及讲解

1. 下面哪些语句会使用到索引，哪些索引起了作用？ ``` CREATE TABLE t1 ( id int unsigned NOT NULL auto_increment, a int unsigned NOT NULL DEFAULT 0, b int unsigned NOT NULL DEFAULT 0, c int unsigned NOT NULL DEFAULT 0, PRIMARY KEY(id), KEY abc (a, b, c) USING BTREE ); (1). SELECT * FROM t1 WHERE a=3 AND b=5 AND c=4; (2). SELECT * FROM t1 WHERE c=4 AND b=6 AND a=3; (3). SELECT * FROM t1 WHERE a=3 AND c=7; (4). SELECT * FROM t1 WHERE a=3 AND b>7 AND c=3; (5). SELECT * FROM t1 WHERE b=3 AND c=4; (6). SELECT * FROM t1 WHERE a>4 AND b=7 AND c=9; (7). SELECT * FROM t1 WHERE a=3 ORDER BY b; (8). SELECT * FROM t1 WHERE a=3 ORDER BY c; (9). SELECT * FROM t1 WHERE b=3 ORDER BY a; ``` #### 题目的详细讲解，欢迎关注 <font color=red size=5> Go后端干货</font> #### Go，后端等技术干货分享，欢迎一起交流学习