Thanks for the idea.
I have changed the datatype to bigint, the result is not changed.
mysql> desc select * from ip_test where startNum <= 3061579775 and
endNum >= 3061579775;
+----+-------------+---------+------+-----------------+------+---------+------+--------+-------------+
| id | select_type | table | type | possible_keys | key | key_len
| ref | rows | Extra |
+----+-------------+---------+------+-----------------+------+---------+------+--------+-------------+
| 1 | SIMPLE | ip_test | ALL | startNum,endNum | NULL | NULL
| NULL | 396528 | Using where |
+----+-------------+---------+------+-----------------+------+---------+------+--------+-------------+
CREATE TABLE `ip_test` (
`startNum` bigint(20) NOT NULL,
`endNum` bigint(20) NOT NULL,
`country` varchar(50) NOT NULL default '',
`province` varchar(50) NOT NULL default '',
`city` varchar(50) NOT NULL default '',
`isp` varchar(100) default NULL,
KEY `startNum` (`startNum`),
KEY `endNum` (`endNum`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 |
在 2010年11月9日 下午5:20，Aveek Misra <aveekm@stripped> 写道：
> I don't see how BETWEEN is not equivalent to (startNum <= and endNum >=). Of
> course please try and let us know if that resolves the issue. But if it doesn't, I suspect
> it is because the indexes are created on columns which are floating point data type.
> That's because floating point numbers are approximate and not stored as exact values.
> Attempts to treat double values as exact in comparison may lead to the kind of issues that
> you are getting. I could be wrong though; but if Johan's trick does not work, you might
> try and change the data type to DECIMAL to see if it helps (or BIGINT if your numbers are
> not using any digits after the decimal since BIGINT and DOUBLE both use 8 bytes for
> storage).
>
