暂时记录下：
SELECT * FROM `kw_user` AS t1 JOIN ( SELECT ROUND( RAND( ) * ( ( SELECT MAX( id ) FROM `kw_user` ) - ( SELECT MIN( id ) FROM `kw_user` ) ) + ( SELECT MIN( id ) FROM `kw_user` ) ) AS id ) AS t2 WHERE t1.id >= t2.id AND 加上删选条件 ORDER BY t1.id LIMIT 1;