\n
\u7d22\u5f15\u8303\u56f4\u67e5\u8be2<\/h3>\n
t33\u8868\u6709\u4e09\u5217\uff0cid,name,birth\u3002 id\u662f\u4e3b\u952e\uff0cname\u662f\u4e8c\u7ea7\u7d22\u5f15,birth\u6ca1\u6709\u7d22\u5f15\u3002\u4e3a\u4ec0\u4e48select * from t33 where name='aaa';\u7528\u5230\u7d22\u5f15\uff0c\u800cselect * from t33 where name>'aaa' \u5219\u4e0d\u7528\u3002<\/p>\r\n\r\n
mysql> mysql> show index from t33;
\r\n+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
\r\n| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
\r\n+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
\r\n| t33 \u00a0 | \u00a0 \u00a0 \u00a0 \u00a0 \u00a00 | PRIMARY \u00a0| \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a01 | id \u00a0 \u00a0 \u00a0 \u00a0 \u00a0| A \u00a0 \u00a0 \u00a0 \u00a0 | \u00a0 \u00a0 \u00a0998446 | \u00a0 \u00a0 NULL | NULL \u00a0 | \u00a0 \u00a0 \u00a0| BTREE \u00a0 \u00a0 \u00a0| \u00a0 \u00a0 \u00a0 \u00a0 | \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 |
\r\n| t33 \u00a0 | \u00a0 \u00a0 \u00a0 \u00a0 \u00a01 | name \u00a0 \u00a0 | \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a01 | name \u00a0 \u00a0 \u00a0 \u00a0| A \u00a0 \u00a0 \u00a0 \u00a0 | \u00a0 \u00a0 \u00a0998446 | \u00a0 \u00a0 NULL | NULL \u00a0 | YES \u00a0| BTREE \u00a0 \u00a0 \u00a0| \u00a0 \u00a0 \u00a0 \u00a0 | \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 |
\r\n+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
\r\n2 rows in set (0.00 sec)<\/p>\r\n\r\n
mysql> explain select * from t33 where name='aaa';
\r\n+----+-------------+-------+------+---------------+------+---------+-------+------+-----------------------+
\r\n| id | select_type | table | type | possible_keys | key \u00a0| key_len | ref \u00a0 | rows | Extra \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 |
\r\n+----+-------------+-------+------+---------------+------+---------+-------+------+-----------------------+
\r\n| \u00a01 | SIMPLE \u00a0 \u00a0 \u00a0| t33 \u00a0 | ref \u00a0| name \u00a0 \u00a0 \u00a0 \u00a0 \u00a0| name | 23 \u00a0 \u00a0 \u00a0| const | \u00a0 \u00a01 | Using index condition |
\r\n+----+-------------+-------+------+---------------+------+---------+-------+------+-----------------------+
\r\n1 row in set (0.00 sec)<\/p>\r\n\r\n
mysql> explain select * from t33 where name>'aaa';
\r\n+----+-------------+-------+------+---------------+------+---------+------+--------+-------------+
\r\n| id | select_type | table | type | possible_keys | key \u00a0| key_len | ref \u00a0| rows \u00a0 | Extra \u00a0 \u00a0 \u00a0 |
\r\n+----+-------------+-------+------+---------------+------+---------+------+--------+-------------+
\r\n| \u00a01 | SIMPLE \u00a0 \u00a0 \u00a0| t33 \u00a0 | ALL \u00a0| name \u00a0 \u00a0 \u00a0 \u00a0 \u00a0| NULL | NULL \u00a0 \u00a0| NULL | 998446 | Using where |
\r\n+----+-------------+-------+------+---------------+------+---------+------+--------+-------------+
\r\n1 row in set (0.00 sec)<\/p><\/p>\n <\/div>\n