mysql的ORDERBYRAND()优化_MySQL

[php] $DBI=new dbi2($__DBserver); $num=$DBI->result('select count(1) as num from article');//获取总条数，数据库引擎为MyISAM采用吧 $num=$num[0]['num']-1; $num=rand(1, $num); $list=$DBI->result('SELECT id FROM acticle ORDER BY viewcount DESC LIMIT ?,1',$num);//利用limit 

[php] $DBI=new dbi2($__DBserver); //在200条范围内取10条随机 $list=$DBI->result('SELECT id FROM (SELECT id FROM acticle ORDER BY viewcount DESC LIMIT ?)X ORDER BY RAND() LIMIT ?',200,10);