用51单片机内部定时器实现数字钟功能，可以显示小时，分，秒，误差很小。-51 single-chip microcomputer with internal timer digital clock function, can display hours, minutes and seconds, the error small.
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001543s ]
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:0.090853s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001931s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001302s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001024s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003152s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000887s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003953s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.015287s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001094s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 197153 [ RunTime:0.015364s ]
