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mysql> show create table shajj_member;
+--------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+--------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| shajj_member | CREATE TABLE `shajj_member` (
`member_id` mediumint( NOT NULL auto_increment,
`username` char(30) NOT NULL,
`password` char(32) NOT NULL,
`failure` tinyint(1) NOT NULL,
`regtime` int(11) NOT NULL,
PRIMARY KEY (`member_id`),
KEY `failure` (`failure`),
KEY `regtime` (`regtime`)
) ENGINE=MyISAM AUTO_INCREMENT=18 DEFAULT CHARSET=utf8 |
+--------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> explain SELECT * FROM shajj_member WHERE member_id IN (16,10,9)\G;
*************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: shajj_member
type: ALL
possible_keys: PRIMARY
key: NULL
key_len: NULL
ref: NULL
rows: 6
Extra: Using where
1 row in set (0.00 sec)
ERROR:
No query specified
WHERE IN 用不上索引 ? |
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