两个sql语句含义相同，不过一个慢一个快，哪位大神解释下

[我刚睡醒]

select a.ip,b.province from orderip a
inner join ip_address b on a.ip between b.startip and b.endip;
where a.ip between 974034371 and 974368307

select a.ip,b.province from (
select ip from orderip
where ip between 974034371 and 974368307) a
inner join ip_address b on a.ip between b.startip and b.endip;

以上两个SQL语句在Mysql中运行，第一个运行时间比较久，第二个很快，谁能解释下
注释：ip，province，startip，endip都加了索引了

[kaixinguo8115]

看一下执行计划

[ACMAIN_CHM]

explain select ... 贴出两个语句的执行计划进行分析即可。