以高效率的方法查找一个数组中的第二大数，数组中的数可以相同.同时对各种可能发生的错误返回相应得错误代码。-find second max number in a high effective method.The number in the array could be the same.meanwhile ,the program return special error code
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.000892s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.065835s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001323s ]
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SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001317s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003653s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000967s ]
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SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.014298s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001294s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 259744 [ RunTime:0.013214s ]
