查看索引： mysql> show index from user_info;
+-----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+-----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| user_info | 0 | PRIMARY | 1 | id | A | 6 | NULL | NULL | | BTREE | | |
+-----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
1 row in set
查看键： mysql> show keys from user_info;
+-----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+-----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| user_info | 0 | PRIMARY | 1 | id | A | 6 | NULL | NULL | | BTREE | | |
+-----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
1 row in set
查看语句的耗时： mysql> set profiling = 1;
Query OK, 0 rows affected mysql> select * from word_list where word like 'b%';
+-----------+-----------------------------------------------+------+
| word | paraphrase | sign |
+-----------+-----------------------------------------------+------+
| backward | a. 向后的; ad. 向后 | F |
| bar | vt. 1.阻止，不许 2.阻碍，阻塞 n. 酒吧，吧台 | F |
| being | n. 1.生物，人 2.存在 | F |
| billboard | n. 布告板,揭示栏,广告牌 | F |
| billion | num.&n. 十亿 | F |
| butterfly | n. 蝴蝶 | F |
+-----------+-----------------------------------------------+------+
6 rows in set mysql> select * from word_list where word like 'c%';
+----------------+----------------------------------+------+
| word | paraphrase | sign |
+----------------+----------------------------------+------+
| capital-driven | a. 追求更多资本的 | F |
| cartoon | n. 动画片; vt. 为...画漫画 | T |
| chart | n. 图，图表 vt. 制图表 | F |
| cholesterol | n. 胆固醇 | F |
| circuit | n. 电路,一圈,巡回 | F |
| civil | a. 国内的,公民的,国民的 | F |
| civilization | n. 文明,文化 | F |
| classical | a. 古典的 | F |
| colonial | a. 殖民地的; n. 殖民地居民 | F |
| colonialism | n. 殖*义 | F |
| commercial | a. 商业的; n. 商业广告 | F |
| comparison | n. 比较 | F |
| competition | n. 比赛,竞争 | F |
| competitive | a. 竞争的,比赛的 | F |
| compute | 计算 | F |
| conference | n. 会议 | F |
| confine | v. 限制,闭居; [计算机] 限制 | F |
| congress | n. 代表大会,国会,议会；男女性交 | F |
| consequence | ad. 因而,所以; n. 结果,后果 | F |
| constant | a. 经常的,不变的; n. 常数,恒量 | F |
| constantly | ad. 不断地,经常地 | F |
| construct | v. 构造,建造,想出 | F |
| constructive | a. 建设性的,构造上的,作图的 | F |
| consumeristic | adj. 消费主义的 | F |
| consumption | n. 消费 | F |
| contribution | n. 贡献 | F |
| cooperate | vi. 合作，协作，配合 | F |
| corporation | n. 公司 | F |
| cycle | n. 循环,周期; v. 骑自行车 | F |
+----------------+----------------------------------+------+
29 rows in set mysql> show profiles;
+----------+------------+----------------------------------------------+
| Query_ID | Duration | Query |
+----------+------------+----------------------------------------------+
| 1 | 0.00065 | select * from word_list where word like 'b%' |
| 2 | 0.00047325 | select * from word_list where word like 'c%' |
+----------+------------+----------------------------------------------+
2 rows in set
查看执行语句的详细情况： mysql> explain select * from word_list where word like 'c%';
+----+-------------+-----------+-------+---------------+---------+---------+------+------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-----------+-------+---------------+---------+---------+------+------+-------------+
| 1 | SIMPLE | word_list | range | PRIMARY | PRIMARY | 92 | NULL | 29 | Using where |
+----+-------------+-----------+-------+---------------+---------+---------+------+------+-------------+
1 row in set
后待补充